Where does “sterna” come from?

sterna (New Latin) comes from English Stern, from English tern, from Middle English terne, from Old French terne, from Latin ternas, from Latin terni, from Latin ter, from Latin terr.

Ancestry of “sterna”, step by step

StepLanguageWordMeaning
1EnglishSternHaving a hardness and severity of nature or manner
2EnglishternAny of various sea birds of the family Sternidae...
3Middle Englishterne—
4Old Frenchternedull, dim
5Latinternasaccusative feminine plural of terni
6Latinternithree each; three at a time
7Latinterthrice
8Latinterr—
9Old Latintris—
10Proto-Italictrēsthree
11Proto-Indo-European*tréyes—

Words derived from “sterna”

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