Computer Science

Algorithm

A step-by-step set of instructions or rules designed to solve a specific problem or perform a task.

Data Structure

Definition: A data structure is a specialized format for organizing, managing, and storing data in a computer's memory so that it can be accessed, retrieved, and modified efficiently. Common examples include Arrays (lists), Hash Maps (dictionaries), Trees, and Graphs.

Variables

Definition: A named storage location in a computer's memory that holds a value, which can change while the program runs.

Function (or Method)

Definition: A reusable block of code that takes an input, performs a specific action, and returns an output.

Caching

Definition: Storing frequently accessed data in a temporary, high-speed storage layer so it can be retrieved much faster than going to the main memory.

Latency

Definition: is the time it takes for data to travel from point A to point B.

API (Application Programming Interface)

Definition: A set of rules and protocols that allows one software application to talk to and interact with another and exchange data.

Operating System (OS)

Definition: The core software that manages a computer's hardware and software resources, providing a foundation for other programs to run.

Concurrency (and Multithreading)

Definition: The ability of a computer to make progress on multiple tasks seemingly at the same time, managing shared resources without conflicting.
managing multiple tasks at once by rapidly switching focus.
The Economics Analogy: Division of Labor. Instead of one artisan building an entire car from start to finish (single-threaded), you have a highly coordinated assembly line where different workers do different tasks simultaneously to increase overall economic output.

Cloud Computing

Definition: Delivering computing services (servers, storage, databases, software) over the internet rather than maintaining local hardware.

Recursion

Definition: A programming method where a function calls itself to break down a problem into smaller, self-similar sub-problems until reaching a defined stopping point (base case).
The Economics Analogy: Corporate Delegation. Think of a corporate hierarchy: a CEO delegates a massive goal to a VP, who delegates a smaller portion to a director, down to a manager, and finally to a worker (the base case). Once the worker finishes, the result is compiled and handed back up the chain, layer by layer, to solve the original company-wide goal.

Database Indexing

Definition: A technique that speeds up data retrieval by creating pointers to where data is stored, avoiding the need to search through every entry sequentially.
The Economics Analogy: A Bookstore Directory or Catalog. Imagine walking into a massive library looking for one specific book. Instead of checking every single shelf one book at a time, you consult the alphabetized index system to go directly to the exact row and shelf.

Encryption (Public-Key)

Definition: A method of securing data using a pair of keys: a public key to scramble (encrypt) the message, and a private key that only the recipient has to unscramble (decrypt) it.
The Economics Analogy: A Mail Slot or Drop Box. Anyone on the street can walk up to a business and slide a confidential envelope into their lockbox mail slot (encrypting with the public key). However, once the envelope drops inside, only the business owner with the unique private key to the back of the mailbox can open it and retrieve the contents.

Garbage Collection

Definition: An automatic process in memory management that detects and reclaims computer memory that is no longer being used by active programs.

Redundancy (and Failover)

Definition: Incorporating duplicate hardware, software, or network components to act as back-ups in the event that primary systems fail.

Bandwidth

is the maximum amount of data that can travel in a given amount of time.
is the size of the truck or the capacity of the highway (e.g., how many tons of goods the truck can carry in that one trip).

Big O Notation

Definition: A mathematical notation used to describe the limiting behavior of an algorithm—specifically, how the execution time or space requirements grow as the input data size increases.
The Economics Analogy: Economies of Scale. It describes how business costs scale relative to production volume.

• O(1) (Constant) is like selling a digital PDF—the cost to serve 1,000,000 customers is the same as serving 1.

• O(N) (Linear) is like a manual consulting service—to double your clients, you must double your hours worked.

• O(N²) (Quadratic) is like an uncoordinated meeting where everyone has to pitch their ideas to everyone else—communication overhead explodes quadratically with every new hire.

Garbage In, Garbage Out (GIGO)

Definition: A fundamental concept holding that flawed or nonsensical input data will inevitably produce flawed or nonsensical output, regardless of how perfect the code or algorithm is.

Client-Server Model

Definition: A distributed application structure that partitions tasks or workloads between service providers (servers) and service requesters (clients).

Load Balancing

Definition: The practice of distributing incoming network traffic or computational workloads across multiple servers to prevent any single server from becoming overwhelmed.

Abstraction

Definition: The process of hiding complex, low-level implementation details of a system and exposing only the essential, high-level features needed to interact with it.
The Economics Analogy: Swiping a Credit Card. When you pay for coffee, you only need to understand the simple interface of tapping your card. You do not need to understand the underlying complexity of payment gateways, clearinghouses, banking networks, or credit risk algorithms happening behind the scenes to buy your drink.

Compiler

translates an entire high-level program into machine code all at once before it runs.

Interpreter

translates and executes the code line-by-line, on the fly, while the program is running.

Deadlock

Definition: A situation where two or more processes are unable to proceed because each is waiting for the other to release a resource it needs.
The Economics Analogy: A Trade War or Regulatory Standoff. Country A refuses to lift steel tariffs until Country B lowers agricultural tariffs. Meanwhile, Country B refuses to lower agricultural tariffs until Country A lifts steel tariffs. Because neither party will compromise first, trade freezes entirely and both economies stall.

Version Control (e.g., Git)

Definition: A software system that tracks, records, and manages changes to a codebase over time, enabling developers to collaborate without overwriting each other's work and revert to earlier states if needed.

Tree

A hierarchy one root node branching into children with no cycle’s leaves are nodes with no children.

JSON

The universal text format for structured data

Proprietary Software

keeps its code private, protected as intellectual property.
is like a patented pharmaceutical drug or Coca-Cola's secret recipe. It is kept strictly under wraps to secure a competitive market advantage, and users must pay a licensing fee to access it.

Hash Function (Hashing)

Definition: An algorithm that takes an input of any size and maps it to a unique, fixed-size string of characters or numerical value (a hash). It is a one-way process used to quickly identify or verify data.
The Economics Analogy: Barcodes and Stock Keeping Units (SKUs). Every single product in a store, regardless of its size, shape, weight, or price, is assigned a standardized, fixed-length barcode. Scanning it instantly identifies the product in the store's database without needing to manually inspect or describe the item.

Inheritance (Object-Oriented Programming)

Definition: A mechanism in OOP where a new class (the child) automatically receives the attributes and behaviors of an existing class (the parent), allowing developers to reuse existing code while adding specialized features.
The Economics Analogy: Corporate Franchising. A new local franchise of McDonald’s automatically "inherits" the parent company's brand name, ingredients, kitchen layout, and business playbook (attributes and methods). However, the local owner can still add specialized regional items to their menu to adapt to local tastes.

Polymorphism (Object-Oriented Programming)

Definition: The ability of different programming objects to respond to the same command or method call in their own unique, customized ways.
The Economics Analogy: Standardized Payment Interfaces. A point-of-sale terminal expects a single command: "Process Payment." It does not care if the consumer pays with physical cash, swipes a credit card, or scans Apple Pay. Each of those payment methods is a different "object" that processes the payment using a completely different system behind the scenes, but they all satisfy the same command interface.

Serialization

Definition: is the process of converting a complex, active memory object into a flat, raw stream of bytes (like JSON or XML) so it can be saved to a file or sent over a network.

Deserialization

is the reverse process of rebuilding that flat byte stream back into a live, structured object in memory.

DNS (Domain Name System)

Definition: The decentralized system that translates human-friendly web domain names (like google.com) into machine-friendly IP addresses (like 142.250.190.46) that computers use to find each other on the network.

Symmetric Cryptography

Definition: An encryption method where the exact same secret key is used both to scramble (encrypt) the message and unscramble (decrypt) it. It is highly efficient for bulk data but requires a secure way to share the key initially.
The Economics Analogy: A Shared Physical Safety Deposit Box. You and your business partner have identical physical keys to a single lockbox at a bank. It is incredibly quick and simple for either of you to lock a document inside or retrieve it. However, the system fails entirely if a thief steals even one of the keys, or if you can't securely meet up to give your partner their copy of the key.

Event Loop (Asynchronous I/O)

Definition: A programming construct that continuously listens for events (like a user click or a completed file download) and dispatches them to be processed, allowing a single-threaded program to manage multiple slow operations without freezing up.

Rate Limiting

Definition: A defensive technique used by web servers to limit the number of requests a user or client can make within a certain timeframe to prevent system abuse and server crashes.

Monolithic Architecture

Definition: A software design pattern where all components, services, and business logic are combined into a single, unified codebase that runs as a single service on a single platform.

Microservices Architecture

Definition: An architectural style that structures an application as a collection of small, highly specialized, and loosely coupled services that run independently and communicate over networks using standardized protocols (like APIs).

Class

A blueprint, template, or data type that defines the structure, attributes (data), and behaviors (functions/methods) that a specific type of entity will have. It is a logical concept and does not occupy memory on its own.

Object

A specific, concrete instance created from that class blueprint. It is a real entity that exists in the computer's memory with actual values assigned to its properties.

Git Merge

Definition: A version control operation that combines the history and changes from a source branch into a target branch, creating a dedicated "merge commit" that marks the exact moment the two histories converged.
The Economics Analogy: A Collaborative Joint Venture. Two separate companies agree to pool their resources for a project. Both companies maintain their individual historical accounting ledgers, tax histories, and employee rosters completely intact. The joint venture is logged in the books as a clear, historical transaction event that links both corporate timelines together, preserving the full paper trail of how both entities operated independently before coming together.

Git Rebase

Definition: A version control operation that takes all the commits from your current branch and reapplies them one by one directly on top of the target branch's latest commit, creating a clean, completely linear project history.
The Economics Analogy: A Corporate Acquisition and Restructuring. Instead of entering a joint venture, a large parent company buys a small startup. Rather than keeping the startup's old ledgers and separate brand intact, the parent company’s auditors rewrite the organizational charts, absorb the startup's assets, and backdate the integration. On paper, it looks as though the startup’s assets and products were built internally by the parent company's team from day one.

Threat Modeling

Definition: A structured, proactive approach to identifying, prioritizing, and analyzing potential security vulnerabilities and system threats, mapping out how an adversary might attack.

Defense-in-Depth

Definition: An information security concept in which multiple layers of security controls are placed throughout an IT system to protect resources, ensuring that a failure in one layer is caught by the next.

Stack Memory Allocation

Definition: A fast, highly organized memory space allocated by the operating system that automatically stores short-lived variables and function calls in a strict, predictable "Last-In, First-Out" (LIFO) order.
The Economics Analogy: Cash in Hand. The physical dollars and quarters sitting in your wallet represent your stack. Accessing and spending it is incredibly fast and frictionless. However, it has a very strict, small capacity—you can't fit a mortgage payment in your pocket. Furthermore, when you get home at night and "close the transaction" of your day, your wallet is cleared out or reset.

Heap Memory Allocation

Definition: A large, unorganized pool of system memory used for dynamic, long-lived data that can scale, shrink, and persist across multiple functions, requiring manual or automated cleanup to prevent waste.
The Economics Analogy: A Corporate Capital Reserve Account. Drawing money from a large, off-site corporate reserve fund takes much more time and administrative overhead (allocating memory). However, it can hold massive, flexible amounts of capital that can fund projects lasting for years. You must also keep strict track of how much you withdraw and ensure you return unused funds to the reserve, or your business will suffer from a "capital leak" (memory leak) and eventually run dry.

Technical Debt

Definition: The implied cost of future restructuring or bug-fixing caused by choosing an easy, fast software solution now instead of a better, more robust approach that takes longer.

Zero-Day Vulnerability

Definition: A security flaw in software that is unknown to the software creator or the public, meaning there are "zero days" to prepare defenses before attackers can exploit it.

Virtual Machines (VMs)

Definition: A software-defined emulation of a physical computer that runs its own complete guest operating system, isolated entirely from other virtual machines on the same hardware.

Containers (e.g., Docker)

Definition: A lightweight package of software that bundles application code together with only the specific dependencies and libraries it needs to run, sharing the host operating system's kernel to run isolated user spaces.

SQL Databases

Definition: Relational database management systems that store data in structured, rigid tables with predefined columns and relationships, using Structured Query Language for strict, transaction-safe queries.
The Economics Analogy: A Standard Double-Entry Bookkeeping Ledger. An accountant's ledger has immutable, predefined columns for Date, Account Number, Debits, and Credits. If an entry does not fit this strict schema, the ledger rejects it. This high-structure environment is incredibly reliable, easy to audit, and perfect for managing financial ledgers where accuracy and consistency are paramount.

NoSQL Databases

Definition: Non-relational databases that store unstructured or semi-structured data in flexible formats (like documents, key-values, or graphs), allowing for rapid scaling and schema changes on the fly.
The Economics Analogy: A Creative Project Brainstorming Board. Instead of a rigid accounting ledger, a marketing team uses a whiteboard. They stick up post-it notes of various sizes, shapes, and colors. If they want to add a new category or attribute, they just write it on a new post-it and slap it on the board. It is highly flexible and scales rapidly for chaotic, fast-changing ideas, though it is much more difficult to audit

Public Key Infrastructure (PKI) & Digital Certificates

Definition: A framework of digital certificates, certificate authorities (CAs), and cryptographic keys used to verify the authentic identity of a website, user, or server on the internet.
The Economics Analogy: Notaries Public and Government Passports. You can't just print a piece of paper claiming you are a registered corporation or a foreign citizen. You must present a passport issued by a trusted government authority (the Certificate Authority) that uses physical security features (cryptographic signatures) that banks and borders can verify to prove you are exactly who you claim to be

Immutable Infrastructure

Definition: An operations model where servers and infrastructure are never updated or modified in place. If a change or patch is needed, new servers are built from a standardized template, and the old ones are destroyed.

Content Delivery Network (CDN)

Definition: A geographically distributed group of servers that work together to provide fast delivery of internet content by caching assets close to where users are physically located.

Statefulness

• The CS Concept: system remembers past interactions and maintains context (the "state") over time across multiple requests.

Graph Theory (Graphs and Nodes)

Definition: A mathematical structure used to model pairwise relations between objects, consisting of "vertices" (or nodes) connected by "edges" (or links).
The Economics Analogy: Global Airline Routes or Financial Transaction Networks. The airports (or banks) are the nodes, and the direct flights (or wire transfers) between them are the edges. Modeling this network allows analysts to instantly identify "critical hubs" (like Atlanta's airport or major clearing houses) that, if shut down, would cascade failures through the entire global system.

Continuous Integration (CI)

Definition: A software development practice where developers frequently merge their code changes into a central repository, triggering automated builds and tests to catch bugs as early as possible.
The Economics Analogy: Just-in-Time Quality Control on an Assembly Line. Instead of assembling an entire car and testing it at the very end (only to discover the engine block is cracked), a modern factory places automated testing sensors at every station. The moment a supplier delivers a piston, or a robot welds a bracket, the line automatically checks that specific component's measurements before allowing it to proceed down the line.

Continuous Deployment (CD)

Definition: A software development practice where every code change that successfully passes the automated testing pipeline is automatically released directly to production and visible to users.
The Economics Analogy: Automated Drop-Shipping. When a customer orders a customized t-shirt online, the order is automatically routed to a digital printing press, manufactured, packaged, and loaded onto a delivery truck without a single human administrator needing to manually review, sign off, or push a button to authorize the shipment.

Statelessness

• The CS Concept: system treats every single request as completely independent; it retains no memory of previous interactions.

Domain-Driven Design (DDD)

Definition: An approach to software development that centers the codebase design on a deep understanding of the real-world business domain and uses a shared "ubiquitous language" between developers and business stakeholders.

Supervised Machine Learning

Definition: A type of machine learning where a model is trained on a labeled dataset, meaning every training input is paired with its correct, pre-verified output.

Unsupervised Machine Learning

Definition: A type of machine learning where a model is fed raw, unlabeled data and must discover hidden patterns, structures, or anomalies on its own without any human guidance or answers.

Array

Definition: A foundational, sequential data structure that stores a collection of elements of the same type in contiguous (back-to-back) memory blocks, allowing for instant access using numerical indices.
The Economics Analogy: A Row of Numbered Safety Deposit Boxes. Imagine a bank vault containing a single, continuous row of physical deposit boxes numbered strictly from 0 to 99. Because the boxes are physically welded together in order, a teller can walk directly to Box #42 instantly (O(1) access speed) without having to read the labels on Box 0 through 41 first.

Linked List

A linear data structure where elements (nodes) are not stored in contiguous memory locations, but are instead linked together dynamically using pointers, where each element contains a reference to the next. It mainly allows efficient insertion and deletion operations

TCP (Transmission Control Protocol)

Definition: A reliable, connection-oriented network protocol that guarantees that all data packets arrive at their destination intact, without errors, and in the exact order they were sent.

UDP (User Datagram Protocol)

Definition: A lightweight, connectionless network protocol that broadcasts data packets continuously without establishing a formal connection, checking for errors, or guaranteeing delivery order.
The Economics Analogy: A Live Public Radio Broadcast. A radio station broadcasts music and news to millions of listeners in real-time. The station doesn't call each listener to check if they heard the last commercial. If a listener drives under a bridge and loses the signal for two seconds, the station doesn't stop the live show to re-broadcast those missed seconds—they just keep streaming, and the listener joins back in on the current frame.

Database Normalization

Definition: The systematic process of structuring a relational database to minimize data redundancy, prevent data anomalies, and improve data integrity.

Edge Computing

Definition: A distributed computing paradigm that processes data closer to the physical location of the user or data source, rather than routing all traffic to a centralized cloud data center.

Encapsulation (Object-Oriented Programming)

Definition: The practice of bundling data and the methods that act on that data inside a single unit (class) while restricting direct external access to internal workings, exposing only a controlled public interface.

Composition (Object-Oriented Programming)

Definition: A design principle where complex objects are constructed by combining simpler, independent objects (a "has-a" relationship) rather than inheriting characteristics directly from a parent class (an "is-a" relationship).

Memory Leak

Definition: An issue that occurs when a computer program allocates memory to hold dynamic data but fails to release that memory back to the system when it is no longer needed, gradually reducing available memory until the program crashes.

Method Overloading

Definition: The ability to define multiple methods within the same class that share the exact same name but accept different quantities or types of input parameters.

Method Overriding

Definition: A mechanism where a child class provides a new, highly specialized implementation of a method that it has already inherited from its parent class, replacing the parent's default behavior.

Environment Variables

Definition: Configuration stored outside the code such as API keys, passwords, URLs and read at runtime

Association

Definition: A basic relationship where two completely independent objects interact with or utilize each other, with no ownership or parent-child hierarchy involved.

Attributes (Properties)

Intuitive Definition: The data variables that belong to a class. Think of them as the nouns or adjectives that describe the state or characteristics of an object.

Embeddings

convert human data (text, images, audio) into long lists of numbers (vectors) that represent their semantic meaning. Positioned so that similar meanings sit close together making meaning searchable.

Vector Databases

stores these numbers and allows you to search for data points that are mathematically "close" to each other in multidimensional space.

Asynchronous

operations allow other tasks to start and run while waiting for a slow task to finish, without pausing the entire program.
is a sit-down diner. The server takes your order, sends it to the kitchen, and immediately goes to serve other tables. You wait for your food, but the rest of the restaurant keeps moving.

Synchronous

operations execute sequentially, blocking subsequent tasks until the current one finishes.
is a drive-thru lane. If the car at the window has a complex, slow order, every single car behind them is completely frozen and blocked from placing or receiving their orders.

Authentication

identifies who an entity is (identity)

Authorization

verifies what that authenticated entity is permitted to do (permissions).

Modularity

Splitting a program into parts that each do one job and connect through clear interfaces

Testing

Automated checks that code behaves as expected

Unit tests

Cover single functions

Integration Tests

Cover whole flows

Logging

A program’s running diary: info, warnings and errors written out with timestamps as it works.

Token

Chunk an LLM actually reads and writes to

Context Window

Maximum number of tokens a model can consider at once

Temperature

Dial for output randomness, near 0 is consistent repeatable answers while near 1 gives varied creative ones

Structured Output

Constraining the model to reply in machine readable schema like JSON so downstream code can parse it reliably

Runtime

(1) *when* a program is actually executing ("this error happens at runtime, not when writing code"); (2) the environment that executes it, like Node.js for JavaScript.

dependency

external code your program relies on

package manager

(npm, pip) downloads, installs, and version-tracks those dependencies so your project is reproducible on any machine.

Middleware

code that sits between the request and your main logic, handling cross-cutting concerns like authentication, logging, or rate limiting before the request reaches its destination. Analogy: airport security — every passenger passes through the same checkpoint before boarding.

Polling

repeatedly asking a service for updates on a schedule (simple, but wasteful and laggy

Webhook

the service pushes to you on an event (efficient, real-time). Know when each is appropriate.

Pointer / Reference

A value that stores the *address* of data rather than a copy of it. Two references can point to the same underlying object, so changing it through one changes it for both — a common source of surprising bugs.