Where does “tern” come from?

tern (Catalan) comes from Latin ternus, from Latin ter, from Latin terr, from Old Latin tris, from Proto-Italic trēs, from Proto-Indo-European *tréyes.

tern (Catalan): set of three, trio

Definitions

set of three, trio

Ancestry of “tern”, step by step

Step	Language	Word	Meaning
1	Latin	ternus	triple, threefold, trinary; three each
2	Latin	ter	thrice
3	Latin	terr	—
4	Old Latin	tris	—
5	Proto-Italic	trēs	three
6	Proto-Indo-European	*tréyes	—

Every word from Proto-Indo-European *tréyes →Every word from Proto-Italic trēs →Every word from Old Latin tris →