AP Computer Science Principles Vocabulary

Abstraction

Pulling out specific differences to make one solution work for multiple problems. Removing detail. Managing complexity.

Aggregation

A computation in which rows from a data set are grouped together to compute a single meaningful value (e.g., average, sum, count).

Algorithm

A precise sequence of instructions for processes that can be executed by a computer.

API

A collection of commands made available to a programmer.

Array

A data structure used to represent a list.

ASCII

The universally recognized raw text format that any computer can understand.

asymmetric encryption

A scheme where the key to encrypt data is different from the key to decrypt.

Bandwidth

Transmission capacity measured by bit rate.

Binary

A way of representing information using only two options.

Bit

A single unit of information in a computer (0 or 1).

Bit rate

The number of bits processed per unit of time.

Boolean

A value of either TRUE or FALSE.

Boolean Expression

An expression that evaluates to true or false.

byte

8 bits.

Caesar Cipher

An encryption technique that shifts the alphabet by a set number.

Cipher

A technique (algorithm) that performs encryption.

Citizen Science

Using large groups of people to help with scientific projects.

Client

A computer that requests data from a server.

Cloud Computing

Using distributed storage and processing over the internet.

code

To write instructions for a computer.

Computationally Hard

A problem that cannot be solved in a reasonable amount of time.

Concatenate

To join together (usually strings).

Conditionals

Statements that run only under certain conditions.

Cracking encryption

Attempting to decode a message without knowing the key.

Creative Commons

A licensing system allowing controlled sharing and reuse of work.

Crowdsourcing

Getting help from many people online to complete a task.

Data Type

A classification of data (e.g., number, string, boolean).

DDos

An attack using many systems to overwhelm a target.

Debugging

Finding and fixing errors in a program.

Decryption

The process of converting encrypted data back to plain text.

Digital divide

The gap between those with and without access to technology.

DNS

A system that translates URLs into IP addresses.

Documentation

Description of how code, functions, or systems work.

Encryption

Encoding messages to keep them secure.

Event

An action that triggers something in a program.

Event-driven program

A program that runs in response to events.

Event handling

Coding that defines how a program responds to events.

Event listener

A command that waits for an event and triggers a function.

Exabyte (EB)

1000 PB or 10^18 bytes.

Expression

Code that evaluates to a value.

For Loop

A loop that repeats a set number of times using a counter.

Function

A reusable block of code that performs a task.

gif

A bitmap image format using lossless compression.

Gigabyte (GB)

1000 MB or a billion bytes.

Global Variable

A variable accessible throughout the entire program.

Heuristic

A problem-solving approach for finding a good-enough solution.

HTTP

A protocol used for transmitting web pages.

IETF

An organization that develops internet standards.

If-Statement

A conditional statement that runs code if a condition is true.

Image

A type of data representing graphics.

Innovation

A new or improved idea or product.

Internet

A network of connected computers.

IP Address

A unique identifier for a device on a network.

Iterate

To repeat a process.

jpg

A lossy compressed image format.

Kilobyte (KB)

1000 bytes.

Latency

Time it takes for data to travel.

Library

A collection of reusable code.

List

A data structure that holds multiple items.

Local Variable

A variable only accessible within a specific scope.

Loop

Repeating a set of instructions.

Lossless Compression

Compression with no loss of data.

Lossy Compression

Compression that removes some data.

Megabyte (MB)

1000 KB or 1,000,000 bytes.

metadata

Data that describes other data.

Models and Simulations

Programs that mimic real-world systems.

modulo

An operation that returns the remainder of division.

Moore's Law

The prediction that computing power doubles every ~2 years.

Net Neutrality

The idea that all internet traffic should be treated equally.

not reasonable time

Typically exponential time complexity.

Open Access

Free access to information or resources.

overflow

An error when numbers exceed storage capacity.

Packets

Small chunks of transmitted data.

Parameter

Input passed into a function.

Peer-to-peer networks

Networks where computers connect directly.

Petabyte (PB)

1000 TB.

phishing

Fraudulent attempts to obtain sensitive information.

Pivot Table

A tool used to summarize data in spreadsheets.

pixel

The smallest unit of a digital image.

png

A lossless image format.

Private Key

A secret key used to decrypt data.

Protocol

Rules for data communication.

Public Key Encryption

Encryption using a public key and private key pair.

Random Substitution Cipher

Encryption replacing letters randomly.

reasonable time

Polynomial time complexity.

Return Value

The output of a function.

RGB

A color model using red, green, and blue.

round-off error

Error from approximating numbers.

Selection

Using conditions to choose which code runs.

sequencing

Executing code step by step.

Server

A computer that provides data to clients.

String

A sequence of characters.

Summary Table

A table summarizing data.

TCP

A protocol ensuring reliable data transmission.

Terabyte (TB)

1000 GB.

UI Elements

On-screen interactive components.

undecidable

A problem that cannot be solved by any algorithm.

URL

A web address.

User Interface

The visual part of a program users interact with.

Variable

A named storage location for data.