Why was "tantrum" trending last week?
1560s, from Middle French corniche (16c.) or directly from Italian cornice "ornamental molding along a wall," perhaps from Latin coronis "curved line, flourish in writing," from Greek koronis "curved object" (see crown). Perhaps influenced by (or even from) Latin cornicem, accusative of cornix "crow" (cf. corbel).
in architecture, the decorated projection at the top of a wall provided to protect the wall face or to ornament and finish the eaves. The term is used as well for any projecting element that crowns an architectural feature, such as a doorway. A cornice is also specifically the top member of the entablature (q.v.) of a Classical order (see order); it is in this case divided into three parts, a bed mold, corona, and cymatium.