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

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

The Nobel Company is said to be perfecting a smokeless powder in which the chief ingredients are nitro-amido- and tri- nitro-benzene.

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