Find the word definition

Douglas Harper's Etymology Dictionary

ter-

word-forming element meaning "thrice, three times," from Latin ter "thrice," from *tris-, from root of three. Compare Latin tertius "third."

The Collaborative International Dictionary

Ter-

Ter- \Ter-\ A combining form from L. ter signifying three times, thrice. See Tri-, 2.

Wiktionary

ter-

pre. three