Definition of: ternary

(tûr′nər·ē) adjective
1. Formed or consisting of three; grouped in threes.
2. Math. Containing three variables; also, pertaining to systems of notation, having three as a base, or radix.
3. Chem. Having three separate parts, as atoms, elements, etc.
4. Metall. Made of an alloy which contains three metals.
—noun plural ·ries A group of three; a triad. [<L ternarius <terni by threes]