Vfs = Flap Safety Speed, the speed which provides a margin of safety during flap retraction after takeoff or a go-around
Vap is sometimes expressed as approach speed
Note that none of these are official designations, but are either manufacturer-use or common-use designations. You'll frequently come across speeds designated by a particular manufacturer that aren't used by other aircraft manufacturers. Nothing springs to mind as a good example, but I'm sure others here will have some.