(umbraculum),
(1.) the ciborium, or canopy, overhanging the altar, imitating a roof supported by pillars.
(2.) The canopy which is borne over the host, or over the head of the pope, on days of ceremony. The name itself is an ancient French term, signifying the richest kind of silks and tissues, especially of gold thread; so called, perhaps, because imported from Baldak, the mediaeval name of Babylon in Persia. — Ducange, Gloss. s.v.