Every type of advertising incurs costs, which are also referred to as "adspend" or "ad spend". The term is composed of the English word "ad" (advertising) and "spend" (expenditure). The term is often mistakenly equated with the advertising budget. The difference is that the advertising budget is the absolute amount of money that is generally available for advertising measures and ad spend represents the exact amount of money that was spent on a specific measure.
An example: An online retailer wants to advertise his products on Google and has an advertising budget of 10,000.00 EUR per month available for this. However, the advertising campaigns only run moderately well and cause costs of 6,000.00 EUR.