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-' also found in these entries (note: many are not synonyms or translations):
Arch of Triumph
- Bermuda Triangle
- Bernoulli trials
- Devil's Triangle
- Golden Triangle
- Monkey Trial
- Pascal's triangle
- Pitri
- TBT
- Tri-Nations Championship
- astronomical triangle
- attrite
- benzotrifluoride
- chlorotrifluoroethylene
- chlorotrifluoromethane
- circular triangle
- clinical trial
- cyclonite
- cyclotrimethylenetrinitramine
- dichlorodiphenyltrichloroethane
- drill
- drilling
- enflurane
- estriol
- field trial
- glyceryl trinitrate
- glyceryl trioleate
- glyceryl tripalmitate
- hunter trials
- maestro
- major triad
- melitriose
- menazon
- methyltrinitrobenzene
- minor triad
- monopod
- multiplet
- nortriptyline
- obedience trial
- oblique triangle
- obtuse triangle
- petri dish
- picloram
- protriptyline
- right triangle
- table tripod
- teapoy
- three
- travail
- trefoil