Meaning

noun upright consisting of a vertical side member of a door or window frame

originFrom Middle English jambe, jaumbe, from Old French jambe (“leg”), from Late Latin gamba (“hock, shank, leg, thigh”), from Ancient Greek καμπή (kampḗ, “turning post, bend or flexure”). Doublet of gam, gamb, gamba, and jambe.

Etymology from Wiktionary, CC BY-SA 3.0