Pleasure is a general term for good feelings. People get pleasure from eating, sleeping, watching TV, or anything else they enjoy.
Pleasure is the opposite of pain. Pain feels bad, but pleasure feels good. People talk about sexual pleasure, but that's just one kind. People get pleasure from delicious foods, great movies, beautiful music, and all sorts of other things. Something as small as a comfortable chair and something as big as your candidate being elected President can bring pleasure. If you had a good time hosting your friends for lunch, you can tell them "It was a pleasure."