Pay per click (PPC) is an internet advertising model used to direct traffic to websites. The name of the model—pay per click—refers to how the advertising is paid for. Every time your advert is clicked on you will pay for the click.
Pay per click is usually said in the same breath as Google AdWords (now just called Google Ads) as it’s the most popular example of this model. Facebook and Twitter have also started using the pay per click model for some of their advertising.