Which combining form is a prefix meaning first?

• A. Aden/o
• B. Hem/o
• C. Lip/o
• D. Prim/o

Answer: (D)

The element that means first is prim/o-. This combining form comes from Latin primus, meaning first, and when it appears as a prefix it signals first in order or importance. You can see it in primary (first in rank or position), primipara or primigravida (a woman who is having her first birth or is pregnant for the first time). The other roots—aden/o (gland), hem/o (blood), lip/o (fat)—identify the body part or substance involved, not the idea of being first. So prim/o is the one that specifically conveys the notion of first.