Mode: Object mode and Edit mode
Menu: Droplist in the header of the 3D view
The pivot point is the point in space around which all rotations, all scalings and all mirror transformations are centered. You can chose among five general modes for your pivot points which can be selected from a drop-down list in the header of any 3D area, as seen here in (Pivot Point modes). Your job is to choose the most efficient type for the task and to position pivot point accurately.
Note that even if the above examples use meshes, the same rules apply for other types (curves, surfaces…) as well.