Which prefix means Across?

• A. Bio-
• B. Peri-
• C. Trans-
• D. Syn-

Answer: (C)

Across is expressed by trans-. This prefix comes from Latin and means across, through, or beyond, signaling movement from one side to another or crossing a boundary. In medical terms it shows up in words like transport (to carry across), transdermal (through the skin), and transfusion (across from donor to recipient). The other prefixes have different meanings: bio- means life, peri- means around, and syn- means together. Those meanings don’t convey crossing, so they don’t fit the sense of “across.”