what is the super button??

[kriti.mysty]

hello... i realize this may not be a big question... but i was going through the desktop effects posts.. and found many shortcuts using a key called super.. and i cant seem to find that on my keyboard. i use a standard full keyboard on my laptop. is there something i am missing.
thank you in advance for answering this query.

[uRock]

The button between Ctrl and Alt that has the Windows logo on it.