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

Perkin, junr., in 1883, that ethylene and trimethylene bromides are capable of acting in such a way on sodium acetoacetic ester as to form tri- and tetra-methylene rings.

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

Repetition of these operations yields tri- and tetradepsides.

From Synthetic Tannins by Grasser, Georg

In addition to the di-eutectic alloys, we have also tri- and tetra-eutectic alloys, and as an example of the latter we may take the bismuth-tin-lead-cadmium eutectic alloy, melting at 71�.

From Scientific American Supplement, No. 508, September 26, 1885 by Various