Entry 1 sense Webster, 1913 Copperplate /(kŏp"pẽr*plāt`)/ · Cop·per·plate · IPA /ˈkɑpərˌpleɪt/ 01 n. A plate of polished copper on which a design or writing is engraved. 1. A plate of polished copper on which a design or writing is engraved. Phrases & compounds Copperplate press — See Plate press, under Plate.