combining form
Etymology: Middle English, from Latin; akin to Greek tri-, Latin tria three — more at three
1. : three
tri arch
tri act
: characterized by or having three or three parts
tri crotic
tri cycle
tri pod
2. : three times or in three ways
tri farious
tri sonant
also : into three
tri sect
3. : trice : every third
tri weekly
tri ennial
4. : containing three atoms, radicals, or groups (of a specified kind)
tri bromide