CPC, or Cost-Per-Click, is a digital advertising model where advertisers pay for each click on their online ad. It is commonly used in search engine advertising and pay-per-click (PPC) campaigns. Advertisers bid on keywords or placements and are charged only when a user clicks on their ad. The cost per click can vary based on factors like keyword competitiveness and ad relevance. CPC provides advertisers with better control over their budget and allows for measurable results by tracking the number of clicks and associated costs.