convex Look up convex at Dictionary.com
1570s, from M.Fr. convexe, from L. convexus "vaulted, arched," pp. of convehere "to bring together," from com- "together" + vehere "to bring" (see vehicle). Possibly from the idea of vaults carried together to meet at the point of a roof. Related: Convexity (c.1600). Convex lens is from 1822.