A Keep

[paulshaz]

where is the keep situated in a castle

[VHG]

The "keep" is the strong central tower, inside the curtain wall round the "castle".

This is where the king or prince would live and keep his money and gold. It would be the strongest part of the castle with thick walls and would be the place eveyone went if the outer walls were breached.

The "white tower" in the Tower of London is a keep
http://prometheus.med.utah.edu/~bwjones/C1705165967/E20070615083458/Media/White%20tower.jpg

To be honest a search in Google on "keep castle" would have found this answer in seconds

http://en.wikipedia.org/wiki/Keep

[VHG]

My first link did not work, try again

http://tinyurl.com/yhuupu3