Meaning

noun a molding that (in section) has the shape of an S with the convex part above and the concave part below

originFrom Middle English *ogeve, egeve, egeove, from Old French œgive, ogive, augive, from Late Latin augiva, of uncertain origin; compare Late Latin ogis (“a support, prop”), Latin augeō (“to increase, strengthen”), Italian and Spanish auge (“highest point of power or fortune, apogee”). Doublet of ogive.

Etymology from Wiktionary, CC BY-SA 3.0