ogee

1. An "s" curve, a convex curve that curves into a concave curve.
In Architecture also known as a Cyma Reversa.

2. A very commonly used Router bit pattern.

An example of an Ogee Pattern:


3. Architecture. A specific shape of arch.

http://chestofbooks.com/architecture/Modern-Buildings-Construction-V5/Arches-Plane-Continued.html