tri-

American  

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

   triacid; triatomic.

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tri- British  

prefix

1. three or thrice

   triaxial

   trigon

   trisect

2. occurring every three

   trimonthly

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Usage

What does tri- mean? Tri- is a combining form used like a prefix meaning “three.” Tri- is often used in a great variety of both everyday and technical terms. Tri- ultimately comes from both Greek treîs, tría and Latin trēs, tria, all of which mean “three.”

Etymology

Origin of tri-

Middle English < Latin, combining form representing Latin trēs, tria, Greek treîs, tría three

Example Sentences

If you have access to pliable pruned fruit tree branches, you can make tri- or quad-podded structures for your summer crops.

From New York Times • Jun. 19, 2013

Among them are the corn-fed chicken itself; modified cornstarch; mono-, tri-, and diglycerides; dextrose; lecithin; yellow corn flour; regular cornstarch; vegetable shortening; partially hydrogenated corn oil.

From "The Omnivore's Dilemma" by Michael Pollan

Frankland had recognized the analogies existing between the chemical properties of nitrogen, phosphorus, arsenic and antimony, noting that they act as tri- or penta-valent.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 1 "Châtelet" to "Chicago" by Various

I wrote my last sheet on the 19th and your father went on that day to Cambridge to be present at the tri- centennial celebration of Trinity College .

From Letters from England by Bancroft, Elizabeth Davis

This is equivalent to a gain in weight of 44 per cent. for the tri- nitrate, and 58 per cent. for the tetra-nitrate.

From Nitro-Explosives: A Practical Treatise by Sanford, P. Gerald (Percy Gerald)