- three or thrice: triaxial, trigon, trisect
- occurring every three: trimonthly
WordReference Random House Learner's Dictionary of American English © 2026
tri-, prefix.
WordReference Random House Unabridged Dictionary of American English © 2026- tri- comes from Greek and Latin, where it has the meaning "three'':triatomic; trilateral.
tri-,
- a combining form meaning "three,'' used in the formation of compound words:triacid; triatomic.
- Latin, combining form representing Latin trēs, tria, Greek treîs, tría three
- Middle English
Collins Concise English Dictionary © HarperCollins Publishers::
tri- prefix
'tri' also found in these entries (note: many are not synonyms or translations):
drill
- maestro
- TBT
- teapoy
- trefoil
- trellis
- tri-
- triangle
- triathlon
- tribrach
- triceps
- triceratops
- trichroism
- triclinium
- tricorn
- trident
- triennium
- trifecta
- trifid
- triforium
- trifurcate
- trigeminal
- triglyph
- trihedral
- trilithon
- trilobite
- trilogy
- trimaran
- trimester
- trimethadione
- trimorphism
- Tri-Nations Championship
- trinomial
- triode
- trioecious
- triphibious
- triphthong
- triplex
- tripod
- triptane
- triptych
- trireme
- trisect
- trishaw
- triskelion
- triune
- trivial
- Arch of Triumph
- astronomical triangle
- attrite