A medical prefix sits at the front of a term and usually signals number, size, position, direction, time, or amount. Here are the high-frequency prefixes with meanings and clinical examples.
| Prefix | Meaning | Example |
|---|---|---|
| a-, an- | without, absence of | apnea, anemia |
| brady- | slow | bradycardia |
| tachy- | fast, rapid | tachycardia |
| dys- | difficult, abnormal, painful | dyspnea, dysphagia |
| hyper- | excessive, above normal | hypertension |
| hypo- | below normal, deficient | hypoglycemia |
| endo- | within, inner | endocarditis |
| peri- | around, surrounding | pericarditis |
| epi- | upon, above | epidermis |
| inter- | between | intercostal |
| intra- | within | intravenous |
| sub- | under, below | subcutaneous |
| supra- | above, over | suprapubic |
| poly- | many, much | polyuria |
| olig-, oligo- | few, scanty | oliguria |
| anti- | against | antibiotic |
| brady- | slow | bradypnea |
| neo- | new | neonatal |
| post- | after, behind | postpartum |
| pre- | before, in front of | preoperative |
| tachy- | rapid | tachypnea |
| macro- | large | macrocyte |
| micro- | small | microscope |
| leuk-, leuko- | white | leukocyte |
| erythr-, erythro- | red | erythrocyte |
| cyan-, cyano- | blue | cyanosis |
A prefix is the beginning of a medical term that modifies its meaning, usually indicating location (sub-, supra-), number (bi-, multi-), time (pre-, post-), or quality (hyper-, hypo-). For example, in 'hypertension', 'hyper-' means excessive.
Around 100 high-frequency prefixes cover roughly 90% of clinical vocabulary. Our prefix decks focus on these, organized by category (location, quantity, color, etc.) for easier recall.
A prefix attaches to the front and modifies meaning; a root names the body part, system, or condition. In 'pericarditis', 'peri-' (around) is the prefix, 'cardi' (heart) is the root, and '-itis' (inflammation) is the suffix.
Often yes — anti-, pre-, sub-, super-, re-, and trans- carry the same meanings in medical and general English. Greek and Latin prefixes (a-/an-, dys-, eu-) are more specific to medical terminology.
Hyper- (excessive), hypo- (deficient), tachy- (fast), brady- (slow), poly- (many), oligo- (few), peri- (around), endo- (inside), ecto-/exo- (outside), and dys- (difficult/abnormal) appear in thousands of clinical terms.