Cost-per-click (CPC) is a type of online advertising model in which an advertiser pays a certain amount of money each time someone clicks on their ad. CPC is commonly used in search engine advertising, where advertisers bid on specific keywords that are relevant to their products or services.

In a CPC model, the advertiser sets a maximum bid for each click on their ad. When a user searches for a particular keyword, the search engine algorithm determines which ads to show based on the bid amount, relevance, and other factors. If the user clicks on the ad, the advertiser is charged the amount of their bid for that click.

CPC is a popular advertising model because it allows advertisers to only pay for the clicks they receive, rather than paying for impressions or views that may not result in any action. This can make advertising more cost-effective and targeted, as advertisers can focus their budget on keywords and audiences that are most likely to convert into customers.