Medical Terminology - Word Parts and Rules

Foundational Concepts of Medical Terminology

  • Copyright and Administrative Overview:

    • Medical Terminology for Healthcare Professions Copyright © 2020 by Andrea Nelson and Katherine Greene is licensed under a Creative Commons Attribution 4.0 International License.

    • Word parts and definitions are derived from "Appendix A: Word Parts and What They Mean" by MedlinePlus (Public Domain).

    • Definitions of medical term examples are derived from Anatomy and Physiology (OpenStax by Betts et al., CC BY 4.0), Concepts of Biology (OpenStax by Fowler et al., CC BY 4.0), and the NCI Dictionary of Cancer Terms by the National Cancer Institute (Public Domain).

  • Learning Objectives:

    • Identify specific word parts in medical terms.

    • Examine and apply rules for building medical terms.

    • Understand the functional difference between a prefix and a suffix.

    • Differentiate prefixes related to body parts, color, direction, physical properties, shape, and quantity.

    • Distinguish suffixes associated with procedures, conditions, and diagnoses.

  • Four Core Word Parts:

    • Prefix: A word part located at the beginning of a medical term that alters or modifies its meaning.

    • Word Root: The core word part that provides the foundational meaning of a medical term.

    • Suffix: A word part located at the end of a medical term that alters or specifies its meaning.

    • Combining Form Vowel: A vowel (most commonly o) used to connect word parts together to facilitate pronunciation.

    • Combining Form: The term used to describe a word root combined with a combining form vowel (e.g., oste/o, arthr/o, ven/o).

  • Analyzing Word Parts in Medical Terms:

    • When breaking down medical terms, slashes are placed between individual word parts, with a slash positioned on each side of a combining form vowel.

    • Osteoarthritis (Oste/o/arthr/itis):

    • Defined as inflammation of bone and joint.

    • Oste/o: Combining form meaning bone.

    • arthr/o: Combining form meaning joint.

    • -itis: Suffix meaning inflammation.

    • Intravenous (Intra/ven/ous):

    • Defined as pertaining to within a vein.

    • Intra-: Prefix meaning within.

    • ven/o: Combining form meaning vein.

    • -ous: Suffix meaning pertaining to.

  • Language Review for Pronunciation and Spelling:

    • Short Vowels: Indicated by lowercase letters (a, e, i, o, u, and sometimes y).

    • Long Vowels: Indicated by uppercase letters (A, E, I, O, U).

    • Consonants: Comprise all remaining letters of the alphabet (b, c, d, f, g, h, j, k, l, m, n, p, q, r, s, t, v, w, x, z).

  • Matching Core Components:

    • Prefix: Word part at the beginning of the term that changes meaning.

    • Suffix: Word part at the end of the term that changes meaning.

    • Word Root: Foundational meaning of a word.

    • Combining Form: A word root with a combining form vowel.

Rules for Building and Defining Medical Terms

  • Rule 1 (Combining Two Combining Forms):

    • When combining two combining forms, always keep the combining form vowel.

    • Example: In Gastr/o/enter/o/logy (The study of the stomach and the intestines), joining the combining form gastr/o (stomach) with enter/o (intestines) retains the combining form vowel o.

  • Rule 2 (Combining a Combining Form with a Suffix Starting with a Consonant):

    • When combining a combining form with a suffix that begins with a consonant, keep the combining form vowel.

    • Example: In Gastr/o/enter/o/logy, joining the combining form enter/o (intestines) with the suffix -logy (meaning study of, which begins with the consonant l) retains the combining form vowel o.

  • Rule 3 (Combining a Combining Form with a Suffix Starting with a Vowel):

    • When combining a combining form with a suffix that begins with a vowel, drop the combining form vowel.

    • Example: In Intra/ven/ous (Pertaining to within the vein), combining ven/o (vein) with the suffix -ous (meaning pertaining to, which begins with the vowel o) requires dropping the combining form vowel o.

  • Rule 4 (Attaching Prefixes):

    • A prefix is placed at the beginning of the word, and no combining form vowel is used following a prefix.

    • Example: In Intra/ven/ous, the prefix intra- (meaning within) is attached directly at the start of the word without any combining form vowel.

  • Rule 5 (Defining Medical Words):

    • When defining a medical word, begin by defining the suffix first, then work from left to right defining the remaining word parts (prefix and word roots).

    • Filler words (such as "a", "the", or "of") may be added to construct grammatically sensible definitions, provided they do not alter the fundamental meaning of the term.

    • Example: Intra/ven/ous is defined by starting with -ous (pertaining to), then intra- (within), and ven/o (vein), producing "Pertaining to within the vein" or "Pertaining to within a vein".

    • In practical context, literal translations become fluent interpretations; suffixes are often assumed rather than explicitly re-stated (e.g., intravenous becomes "within the vein").

  • Exceptions to Rules ("Rebels"):

    • Language rules provide the foundation for building medical vocabulary, but exceptions exist and are referred to as rebels.

Common Prefixes in Medical Terminology

  • Overview and Study Technique:

    • Prefixes are positioned at the start of a term to modify its core meaning.

    • Accurate spelling and pronunciation of prefixes are essential.

    • Recommended learning technique: Review common medical prefixes, identify standard English words sharing those prefixes, and compare them with medical usages.

  • Alphabetical List of Common Prefixes:

    • A-, An-: Without; Lacking (Example: Anemia)

    • Andr/o-: Male (Example: Androgen)

    • Anti-: Against (Example: Anticholinergic drugs)

    • Auto-: Self (Example: Autocrine)

    • Bio-: Life (Example: Biology)

    • Chem/o-: Chemistry (Example: Chemotherapy)

    • Contra-: Against (Example: Contraception)

    • Cyt/o-: Cell (Example: Cytokine)

    • Dis-: Separation; Taking apart (Example: Dissection)

    • Dys-: Difficult; Abnormal (Example: Dyspnea)

    • Eu-: Good; Well (Example: Eupnea)

    • Fibr/o-: Fiber (Example: Fibrosis)

    • Gluco-, Glyco-: Glucose; Sugar (Example: Glycogen)

    • Gyn/o-, Gynec-: Female (Example: Gynecology)

    • Hydr/o-: Water (Example: Hydrocephalus)

    • Idio-: Self; One’s own (Example: Idiopathic)

    • Lyso-, Lys-: Break down; Destruction; Dissolving (Example: Lysosome)

    • Mal-: Bad; Abnormal (Example: Malignant)

    • Myc/o-: Fungus (Example: Mycetoma)

    • Necr/o-: Death (Example: Necrosis)

    • Neo-: New (Example: Neonate)

    • Oxy-: Sharp; Acute; Oxygen (Example: Oxytocin)

    • Pan-, Pant/o-: All or everywhere (Example: Pancytopenia)

    • Pharmaco-: Drug; Medicine (Example: Pharmacist)

    • Re-: Again; Backward (Example: Rejuvenation)

    • Somat/o-, Somatico-: Body; Bodily (Example: Somatic cell)

Anatomical and Body Part Prefixes

  • Alphabetical List of Body Part Prefixes:

    • Acous/o-: Hearing (Example: Acoustic meatus)

    • Aden/o-: Gland (Example: Adenoid)

    • Adip/o-: Fat (Example: Adipocyte)

    • Adren/o-: Gland (Example: Adrenal cortex)

    • Angi/o-: Blood vessel (Example: Angioplasty)

    • Arteri/o-: Artery (Example: Arteriole)

    • Arthr/o-: Joint (Example: Arthroplasty)

    • Bucc/o-: Cheek (Example: Buccal cavity)

    • Bronch/i-: Bronchus (Example: Bronchioles)

    • Burs/o-: Bursa (Example: Bursa)

    • Carcin/o-: Cancer (Example: Basal cell carcinoma)

    • Cardi/o-: Heart (Example: Cardiology)

    • Cephal/o-: Head (Example: Cephalic flexure)

    • Chol-: Bile (Example: Cholesterol)

    • Chondri-: Cartilage (Example: Chondrosarcoma)

    • Coron-: Heart (Example: Coronary arteries)

    • Cost-: Rib (Example: Costal cartilage)

    • Crani/o-: Brain (Example: Cranium)

    • Cutane-: Skin (Example: Cutaneous)

    • Cyst/o-, Cysti-: Bladder or sac (Example: Cystoscopy)

    • Derm-, Dermat/o-: Skin (Example: Dermatologist)

    • Duoden/o-: Duodenum (Example: Duodenitis)

    • Gastr-: Stomach (Example: Gastrectomy)

    • Gloss-: Tongue (Example: Glossectomy)

    • Hem-, Hema-, Hemat-, Hemo-, Hemat/o-: Blood (Example: Hematopoiesis)

    • Hepat/o-, Hepatico-: Liver (Example: Hepatic portal system)

    • Hist/o-, Histio-: Tissue (Example: Histology)

    • Hyster/o-: Uterus (Example: Hysterectomy)

    • Ileo-: Ileum (Example: Ileostomy)

    • Ischi/o-: Ischium (Example: Ischial tuberosity)

    • Kerat/o-: Cornea (eye or skin) (Example: Keratin)

    • Lacrim/o-: Tear (from your eyes) (Example: Lacrimal fluid)

    • Lact/o-, Lacti-: Milk (Example: Lactose)

    • Laryng/o-: Larynx (Example: Laryngitis)

    • Lingu/o-: Tongue (Example: Lingual tonsil)

    • Lip/o-: Fat (Example: Lipolysis)

    • Lymph/o-: Lymph (Example: Lymphocyte)

    • Mamm-, Mast/o-: Breast (Example: Mammary glands)

    • Mening/o-: Meninges (Example: Meningitis)

    • Muscul/o-: Muscle (Example: Musculoskeletal)

    • My/o-: Muscle (Example: Myocardium)

    • Myel/o-: Spinal cord or bone marrow (Example: Myelin)

    • Nephr/o-: Kidney (Example: Nephron)

    • Neur/i-, Neur/o-: Nerve (Example: Neuron)

    • Oculo-: Eye (Example: Oculomotor nerve)

    • Onco-: Tumor; Bulk; Volume (Example: Oncogene)

    • Onych/o-: Fingernail; Toenail (Example: Onychodystrophy)

    • Oo-: Egg; Ovary (Example: Oocyte)

    • Oophor/o-: Ovary (Example: Oophorectomy)

    • Op-, Opt-: Vision (Example: Optic nerve)

    • Ophthalm/o-: Eye (Example: Ophthalmic artery)

    • Orchid/o-, Orchio-: Testis (Example: Orchidectomy)

    • Orth/o-: Straight; Normal; Correct (Example: Orthostatic)

    • Osseo-: Bony (Example: Osseous tissue)

    • Ossi-: Bone (Example: Ossicles)

    • Ost-, Oste/o-: Bone (Example: Osteoporosis)

    • Ot/o-: Ear (Example: Otolaryngologist)

    • Ovar/i-, Ovario-, Ovi-, Ovo-: Ovary (Example: Ovarian follicle)

    • Phalang-: Phalanx (Example: Phalanges)

    • Pharyng/o-: Pharynx; Throat (Example: Pharyngeal tonsil)

    • Phleb/o-: Vein (Example: Phlebotomist)

    • Phren/i-, Phreno-, Phrenico-: Diaphragm (Example: Phrenic nerve)

    • Pleur-, Pleur/a-, Pleur/o-: Rib, pleura (Example: Pleural cavity)

    • Pneum/a-, Pneumat/o-: Air; Lung (Example: Pneumonia)

    • Proct/o-: Anus; Rectum (Example: Proctoscopy)

    • Prostat-: Prostate (Example: Prostatectomy)

    • Pseudo-: False (Example: Pseudostratified)

    • Psych/o-, Psyche-: Mind (Example: Psychiatrist)

    • Radio-: Radiation; Radius (Example: Radioisotopes)

    • Ren/o-: Kidney (Example: Renal cortex)

    • Retin-: Retina (of the eye) (Example: Retinitis pigmentosa)

    • Rhin/o-: Nose (Example: Rhinoscope)

    • Salping/o-: Tube (Example: Salpingo-oophorectomy)

    • Sarco-: Muscular; Flesh-like (Example: Sarcomere)

    • Schiz/o-: Split; Cleft (Example: Schizophrenia)

    • Sclera-, Sclero-: Hardness (Example: Sclerosis)

    • Sigmoid/o-: Sigmoid colon (Example: Sigmoidoscopy)

    • Sperma-, Spermo-, Spermato-: Sperm (Example: Spermatocyte)

    • Splen/o-: Spleen (Example: Splenomegaly)

    • Sten/o-: Narrowed; Blocked (Example: Stenosis)

    • Stern-: Sternum (Example: Sternoclavicular joint)

    • Stom/a-, Stomat/o-: Mouth (Example: Stomatitis)

    • Thorac/o-, Thoracico-: Chest (Example: Thoracic cavity)

    • Thromb/o-: Blood clot (Example: Thrombolytic)

    • Thyr/o-: Thyroid gland (Example: Thyroiditis)

    • Trache/o-: Trachea (Example: Trachealis)

    • Tympan/o-: Eardrum (Example: Tympanic membrane)

    • Ur/o-: Urine (Example: Urologist)

    • Vagin-: Vagina (Example: Vaginal)

    • Varic/o-: Duct; Blood vessel (Example: Varicose veins)

    • Vasculo-: Blood vessel (Example: Vasculitis)

    • Ven/o-: Vein (Example: Venae cavae)

    • Vertbr-: Vertebra; Spine (Example: Vertebral column)

Prefixes for Color, Physical Properties, Direction, and Quantity

  • Color Prefixes:

    • Chlor/o-: Green (Example: Chlorophyll)

    • Chrom-, Chromato-: Color (Example: Chromosome)

    • Cyano-: Blue (Example: Cyanosis)

    • Erythr/o-: Red (Example: Erythrocyte)

    • Leuk/o-: White (Example: Leukocyte)

    • Melan/o-: Black (Example: Melanin)

  • Physical Property and Shape Prefixes:

    • Cry/o-: Cold (Example: Cryotherapy)

    • Elect-: Electrical activity (Example: Electrocardiogram)

    • Kin/o-, Kine-, Kinesi/o-: Movement (Example: Kinetic energy)

    • Kyphy/o-: Humped (Example: Kyphosis)

    • Rhabd/o-: Rod-shaped; Striated (Example: Rhabdomyosarcoma)

    • Phot/o-: Light (Example: Photoreceptor)

    • Reticul/o-: Net (Example: Reticulocytes)

    • Scoli/o-: Twisted (Example: Scoliosis)

    • Therm/o-: Heat (Example: Thermotherapy)

  • Direction and Position Prefixes:

    • Ab-, Abs-: Away from (Example: Abductor)

    • Ad-: Towards (Example: Adductor)

    • Ante-: Before; Forward (Example: Antenatal)

    • Circum-: Around (Example: Circumcision)

    • Cycl-: Circle; Cycle (Example: Cyclic neutropenia)

    • De-: Away from; Ending (Example: Dehydration)

    • Dia-: Across; Through (Example: Diagnosis)

    • Ect/o-, Exo-: Outer; Outside (Example: Exocrine gland)

    • End/o-, Ent-, Enter/o-: Within; Inner (Example: Endocrine gland)

    • Epi-: Upon; Outside of (Example: Epidermis)

    • Ex-, Extra-: Beyond (Example: Expiration)

    • Infra-: Beneath; Below (Example: Infratemporal fossa)

    • Inter-: Between (Example: Interstitial fluid)

    • Intra-: Within (Example: Intracellular fluid)

    • Meso-: Middle (Example: Mesoderm)

    • Meta-: Beyond; Change (Example: Metabolism)

    • Para-: Alongside; Abnormal (Example: Parathyroid glands)

    • Path/o-: Disease (Example: Pathologist)

    • Peri-: Around (Example: Pericardium)

    • Post-: Behind; After (Example: Postpartum)

    • Pre-: Before; In front (Example: Precancerous)

    • Retro-: Backward; Behind (Example: Retroperitoneum)

    • Sub-: Under (Example: Subcutaneous layer)

    • Super-: Above (Example: Superior)

    • Supra-: Above; Upon (Example: Supraglottis)

    • Sy-, Syl-, Sym-, Syn-, Sys-: Together (Example: Syndrome)

    • Trans-: Across; Through (Example: Transdermal)

  • Quantity Prefixes:

    • Bi-: Two (Example: Biceps)

    • Brady-: Slow (Example: Bradycardia)

    • Diplo-: Double (Example: Diploid)

    • Hemi-: Half (Example: Hemihypertrophy)

    • Hetero-: Other; Different (Example: Heterogeneous)

    • Homo-: Same (Example: Homozygous genotype)

    • Hyper-: Above; Beyond; Excessive (Example: Hypertension)

    • Hypo-: Under; Deficient (Example: Hypotension)

    • Iso-: Equal; Like (Example: Isointense)

    • Macro-: Large; Long; Big (Example: Macrophage)

    • Mic-, Micro-: Small (Example: Microglia)

    • Mon-, Mono-: One (Example: Monocyte)

    • Olig/o-: Few; Little (Example: Oliguria)

    • Poly-: Many; Excessive (Example: Polyuria)

    • Quadri-: Four (Example: Quadriceps)

    • Semi-: Half (Example: Semilunar valves)

    • Tachy-: Fast (Example: Tachycardia)

    • Tetra-: Four (Example: Tetralogy of Fallot)

    • Tri-: Three (Example: Triceps)

    • Uni-: One (Example: Unicellular)

  • Concept Check Review Questions & Answers:

    • Directional Differences: Inter- means between, infra- means beneath or below, and intra- means within.

    • Cell Color Identification: An erythrocyte is red (erythr/o-); a leukocyte is white (leuk/o-).

    • Around something else: Circum- or Peri- can be used.

    • Within something else: End/o-, Ent-, Enter/o-, or Intra- can be used.

    • Below something else: Infra-, Sub-, or Hypo- can be used.

General and Diagnostic Suffixes

  • Overview and Workplace Function:

    • Suffixes are located at the end of medical terms and alter the term's meaning.

    • Correct spelling and pronunciation are vital.

    • While suffixes may not always be explicitly stated in spoken definitions within healthcare workplaces, they are always clearly written in medical transcription and written reports.

  • Alphabetical List of Common Suffixes:

    • -ac: Pertaining to (Example: Cardiac)

    • -blast, -blasto, -blastic: Bud; Germ (Example: Myeloblast)

    • -cyte, -cytic: Cell (Example: Thrombocyte)

    • -dynia: Pain; Swelling (Example: Thoracodynia)

    • -eal, -ial: Pertaining to (Example: Esophageal)

    • -ectasis: Expansion; Dilation (Example: Atelectasis)

    • -emia: Blood condition (Example: Anemia)

    • -ia: Condition (Example: Hemophilia)

    • -iasis: Condition; Formation of (Example: Psoriasis)

    • -ism: Condition (Example: Hypothyroidism)

    • -ites, -itis: Inflammation (Example: Arthritis)

    • -ity: Pertaining to (Example: Immunity)

    • -ium: Structure or tissue (Example: Epithelium)

    • -lysis, -lytic: Break down; Destruction; Dissolving (Example: Osteolytic)

    • -malacia: Softening (Example: Osteomalacia)

    • -megaly: Enlargement (Example: Acromegaly)

    • -oid: Resembling (Example: Arachnoid trabeculae)

    • -oma: Tumor (Example: Angiosarcoma)

    • -osis: Condition; Usually abnormal (Example: Endometriosis)

    • -ous: Pertaining to (Example: Aqueous)

    • -pathy: Disease (Example: Lymphadenopathy)

    • -penia: Deficiency; Lack of (Example: Thrombocytopenia)

    • -phagia, -phagy: Eating; Swallowing (Example: Dysphagia)

    • -phasia: Speech (Example: Aphasia)

    • -plasia, -plastic: Growth (Example: Hyperplasia)

    • -plegia: Paralysis (Example: Hemiplegia)

    • -pnea: Breathing (Example: Sleep apnea)

    • -poiesis: Production (Example: Hemopoiesis)

    • -ptosis: Falling; Drooping (Example: Apoptosis)

    • -rrhage, -rrhagic: Bleeding (Example: Hemorrhage)

    • -rrhea: Flow or discharge (Example: Diarrhea)

    • -sclerosis: Hardening (Example: Arteriosclerosis)

    • -sis: Condition (Example: Agranulocytosis)

    • -stasis: Level; Unchanging (Example: Homeostasis)

    • -trophy: Growth (Example: Hypertrophy)

    • -uria: In the urine (Example: Anuria)

Procedure and Surgical Suffixes

  • Alphabetical List of Procedure Suffixes:

    • -centesis: Surgical puncture to remove fluid (Example: Thoracentesis)

    • -desis: Surgical binding (Example: Pleurodesis)

    • -ectomy: Cut out; Removal (Example: Mastectomy)

    • -gram: Record; Picture (Example: Electrocardiogram)

    • -graph: Instrument used to create a record or picture (Example: Electrocardiograph)

    • -graphy: To record or take a picture (Example: Echocardiography)

    • -meter: Device used for measuring (Example: Sphygmomanometer)

    • -opsy: Visual examination (Example: Biopsy)

    • -ostomy: Opening (Example: Colostomy)

    • -otomy: Incision (Example: Laparotomy)

    • -pexy: Surgical fixation (Example: Oophoropexy)

    • -plasty: Surgical reconstruction (Example: Vertebroplasty)

    • -scope: For examining (Example: Endoscope)

    • -scopy: Examine (Example: Endoscopy)

  • Concept Check Review Questions & Answers:

    • Distinction between -gram, -graph, and -graphy:

    • -gram: Refers to the resulting record or picture itself (e.g., electrocardiogram).

    • -graph: Refers to the instrument used to create the record or picture (e.g., electrocardiograph).

    • -graphy: Refers to the process or act of recording or taking a picture (e.g., echocardiography).

    • Suffixes denoting a condition or disease: -ia, -iasis, -ism, -osis, -pathy, -sis, -ites, and -itis.