Pur is a root meaning which substance?

• A. Blood
• B. Pus
• C. Muscle
• D. Fat

Answer: (B)

Pur- denotes pus. In medical terms, roots point to the substance or concept at the heart of the word, and pur- specifically shows up in words describing pus as found in infections—purulent means containing or producing pus, and purulence refers to the presence of pus. This is distinct from other bodily substances: blood would be indicated by hem- or hemat-, muscle by myo- or sarco-, and fat by adip- or lip-. So pur- is the correct meaning because it directly ties to pus and its clinical contexts.