tri-

tri- Word Origin

1. a combining form meaning “three,” used in the formation of compound words: triacid; triatomic.

Origin of tri- Middle English Latin, combining form representing Latin trēs, tria, Greek treîs, tría three British Dictionary definitions for tri- tri- prefix

1. three or thricetriaxial; trigon; trisect
2. occurring every threetrimonthly

Word Origin for tri- from Latin trēs, Greek treis Word Origin and History for tri-

word-forming element meaning “three,” from Latin tres (neuter tria) or Greek treis (neuter tria) “three” (see three).

tri- in Medicine tri- pref.

1. Three:tricuspid.
2. Containing three atoms, molecules, or groups:triacetic acid.