cy·ma 
(sīmə)
(sīmə)n.
Either of two moldings, cyma recta or cyma reversa, having an undulating or S-shaped profile, used especially in classical architecture. Also called cymatium.
[New Latin cȳma, from Greek kūma, wave, cyma, from kuein, to swell; see keuə- in the Appendix of Indo-European roots.]
cymatop: cyma recta
bottom: cyma reversa