A thing with three components; a set of three things.
Any of various seabirds of the subfamily Sternidae (of the family Laridae) that are similar to gulls but are smaller and have a forked tail.
Consisting of three components; ternate, threefold, triple.
The number three; three things together; a ternary or triplet.
A section of paper for a book containing three double leaves or twelve pages.