An archivolt (or voussure) is an ornamental molding or band following the curve on the underside of an arch.[1] It is composed of bands of ornamental moldings (or other architectural elements) surrounding an arched opening, corresponding to the architrave in the case of a rectangular opening. The word is sometimes used to refer to the under-side or inner curve of the arch itself (more properly, the intrados).
The word originates in the Italian (or French) equivalents of the English words arch and vault.