Pay Per Click (PPC) and Cost Per Click (CPC) are simple terms for advertisers and publishers
Advertisers pays money to publisher, by buying traffic with PPC ads. You earn money from your website by CPC ads which are actually PPC ads to the advertisers. Both CPC and PPC refer to the cost of a click of an ad displayed on a web page.
The difference between these terms is the advertisers pay the publishers for every click on a banner that is published on their website. Therefore, the advertisers pay publishers via PPC ads and the publishers earn from the PPC ads when running them as CPC ads on their website.
So simply the advertisers buy traffic with PPC ads running on publishers’ websites and the publishers earn money by running the CPC ads (PPC ads by the advertisers) on their site.