What’s the difference between CPC & CPM ?

I am realy confused guys,
Do CPM means that I have put a banner on my site & people dnt need to click on it. They just have to visit my pages ?
or they still have to click on my CPM ads to make me money ?
if yes than what is difference b/w cpm & cpc?
If this one is silly question, forgive me.

thnx

Original post by intex