A group of three things; a trio, threesome or tierce.
Arranged in groups of three.
Having three variables.
To the base three.
Containing, or consisting of, three different parts, as elements, atoms, groups, or radicals, which are regarded as having different functions or relations in the molecule.
Made up of three things.
The number three; three things together; a ternary or triplet.
A section of paper for a book containing three double leaves or twelve pages.