English

threeside

From three + side.

A compound of three + side

Proto-Indo-European *tréyes

Proto-Germanic *þrīz

Proto-West Germanic *þrīʀ

Old English þrī

Middle English thre

English three

Proto-Germanic *sīdaz ‘drooping’

Proto-Germanic *sīdǭ ‘side’

Old English sīde ‘side’

Middle English side

English side

Today it means

noun Any object or shape consisting of three sides; triangle.

Language periods are conventional ranges, not dates for this word.

Etymograph / threeside