Income received in advance, also known as unearned revenue or deferred revenue, refers to the money a company receives from its customers before it has provided the goods or services. It is considered a liability on the company's balance sheet until the goods or services are delivered. Once the goods or services are provided, the liability is reduced, and the revenue is recognized as earned. This type of income is common in industries such as subscription-based services, where customers pay in advance for future services.