What is the full form of "CPC"?

Cost per click (CPC) is an online advertising revenue model that websites use to bill advertisers based on the number of times visitors click on a display ad attached to their sites.
The primary alternative is the cost per thousand (CPM) model, which charges by the number of ad impressions, or views, of the display ad, regardless of whether or not a viewer clicks on the ad.
The cost per click model is also known as pay per click (PPC).