A root (combining form) carries the core meaning of a medical term, usually naming a body part or system. These are the most common roots with meanings, examples, and the systems they belong to.
| Root | Meaning | Examples | System |
|---|---|---|---|
| cardi(o)- | heart | cardiomegaly, carditis | Cardiology |
| angi(o)- | vessel, duct | angioplasty, angiography | Cardiology |
| thromb(o)- | clot | thrombosis, thrombocytopenia | Hematology |
| hem(o)-, hemat(o)- | blood | hematoma, hemolysis | Hematology |
| encephal(o)- | brain | encephalopathy, encephalitis | Neurology |
| neur(o)- | nerve | neuropathy, neuralgia | Neurology |
| my(o)- | muscle | myopathy, myocardial | Musculoskeletal |
| arthr(o)- | joint | arthralgia, arthritis | Musculoskeletal |
| oste(o)- | bone | osteoporosis, osteonecrosis | Musculoskeletal |
| hepat(o)- | liver | hepatitis, hepatomegaly | Gastroenterology |
| gastr(o)- | stomach | gastroparesis, gastritis | Gastroenterology |
| enter(o)- | intestine | enteritis, enterocolitis | Gastroenterology |
| col(o)-, colon(o)- | colon | colitis, colonoscopy | Gastroenterology |
| nephr(o)- | kidney | nephritis, nephrology | Nephrology |
| cyst(o)- | bladder, sac | cystitis, cystoscopy | Nephrology |
| pulmon(o)- | lung | pulmonary, pulmonitis | Pulmonology |
| bronch(o)- | bronchus | bronchitis, bronchospasm | Pulmonology |
| derm(a)-, dermat(o)- | skin | dermatitis, dermatology | Dermatology |
| ophthalm(o)- | eye | ophthalmology, ophthalmoplegia | Sensory |
| ot(o)- | ear | otitis, otoscopy | Sensory |
| rhin(o)- | nose | rhinitis, rhinoplasty | Sensory |
| onc(o)- | tumor, mass | oncology, oncogenesis | Pathology |
| cyt(o)- | cell | cytology, cytotoxic | Pathology |
| hist(o)- | tissue | histology, histopathology | Pathology |
| path(o)- | disease, suffering | pathology, neuropathy | Pathology |
| lith(o)- | stone, calculus | lithiasis, lithotripsy | Nephrology |
| trache(o)- | trachea, windpipe | tracheotomy, tracheitis | Pulmonology |
| cephal(o)- | head | cephalic, hydrocephalus | Neurology |
A root word names the core anatomical, physiological, or pathological subject of a medical term — usually a body part or system. Cardi (heart), nephr (kidney), hepat (liver), and neur (nerve) are common examples.
Roughly 150–200 roots cover the body's major systems. Mastering them unlocks thousands of compound terms because the same root combines with many prefixes and suffixes.
Roots usually take an 'o' (sometimes 'i') when joined to another word part, called a combining form (e.g., cardi-o-megaly). The vowel makes pronunciation smoother and is dropped before a vowel-starting suffix (cardi-itis → carditis).
Both are common. Greek roots typically describe disease and function (nephr-, hepat-, derm-); Latin roots describe anatomy in clinical contexts (ren-, hepatic-, cutane-). Many body parts have both Greek and Latin roots.
Cardi (heart), pulmon/pneumon (lung), gastr (stomach), hepat (liver), nephr/ren (kidney), neur (nerve), oste (bone), my (muscle), derm (skin), and hem/hemat (blood) appear in the majority of clinical vocabulary.