Introduction to Medical Terminology Practice Test 2026 - Free Medical Terminology Practice Questions and Study Guide

The suffix -osis indicates a state or condition, usually one that is abnormal or disease-related. It turns a root into a noun that names how the body is in a particular condition. That’s why it’s read as “abnormal condition.” For example, neurosis refers to an abnormal mental state, cirrhosis to a liver disease, and psoriasis to a skin condition. This suffix isn’t used to mean a process (that’s typically -ation or similar) or to mean “pertaining to” (which would use endings like -al or -ic). (Note: a rare exception is osmosis, a process in biology, but in medical terminology the common use of -osis points to an abnormal condition.)