polygon
meaning
a figure, esp. a closed plane figure, having three or more, usually straight, sides.

origin
Origin: 1560–70; < L polygōnum < Gk polýgōnon, n. use of neut. of polýgōnos many-angled.
etymology
1571, from L. polygonum, from Gk. polygon "polygon," from neut. of polygonos "many-angled," from polys "many" + gonia "angle"


convex
meaning
having a surface that is curved or rounded outward.

origin
1565–75; < L convexus equiv. to con- con- + -vexus, perh. < *wek-sos, deriv. of base of vehere to convey, if original sense was "brought together (to a single point)"

etymology
1571, from M.Fr. convexe, from L. convexus "vaulted, arched," pp. of convehere "to bring together," from com- "together" + vehere "to bring". Possibly from the idea of vaults carried together to meet at the point of a roof.

concave
meaning
curved like a segment of the interior of a circle or hollow sphere; hollow and curved.

origin
1375,“1425; late ME (< MF) < L concavus, hollow

etymology
1571, from L. concavus "hollow," from com- intensive prefix + cavus "hollow"