Graphics options terminology - what do they mean?

I'd be greatful if someone could let me know what these terms mean and how much impact they have on gameplay:
1. antialiasing
2. bump maps
3. vertical sync
4. specular

Also, could you let me know how to measure the framerate. Enter com_showFPS 1, but where do i do that - whilst playing the game somehow? How exactly?

Thanks.

1. Anti-aliasing - A method of smoothing the edges of objects on the screen, and giving everything an overall smooth appearance.

2. Bump maps - A method of creating the illusion of surface detail by altering shadows and highlights according to a player's position. Usually done using a greyscaled image which defines depth and height areas with more detail than is (usually) contained within the actual geometry.

3. Vertical Synchronization - Caps the framerate of the game (or whatever it is you're using) at the refreh rate of your monitor.

4. Specularity - A method of mapping dynamic highlights on an object.

Com_showfps must be entered in the console. The console can be accessed at any time by pressing ctrl+alt+~ (~ = tilde. Usually located to the left of the 1 key)

thanks again amaster

Amaster said:

3. Vertical Synchronization - Caps the framerate of the game (or whatever it is you're using) at the refreh rate of your monitor.

Actually that's just a side-effect. Vertical Sync forces the card to wait to display the next frame until the monitor returns to the top of the screen to start the next scan down, drawing the image. The purpose of this is to reduce image "tearing", where the monitor draws half of one frame at the top of the screen, then half of the enxt frame on the same scan, causing a horzonatal line to appear to "tear" the image.

(I'm sure you know that Amaster, I'm just in a picky mood.)