1. expandable metal or wooden wedge used by printers to lock up a form within a chase • Syn: coign, coigne • Hypernyms: wedge 2. the keystone of an arch • Syn: coign, coigne • Hypernyms: keystone, key, headstone 3.(architecture) solid exterior angle of a building; especially one formed by a cornerstone • Syn: corner • Topics: architecture • Hypernyms: structure, construction • Part Holonyms: building, edifice