Emily Dickinson Lexicon

BALD'A-CHIN, n. [It. baldacchino; Sp. baldaquino, a rich silk or canopy, carried over the host. Du Cange. Lunier deduces it from the name of a city in Babylonia.]

In architecture, a building in form of a canopy, supported by columns, and often used as a covering to insulated altars; sometimes used for a shell over a door. – Encyc. Johnson.