What is definition of deferred revenue and how you pass the journal entries in books?

Deferred revenues are revenues received in advance for which services and or goods are to be provided to the customer at a later date. These are UNEARNED at the time of receipt and are considered liabilities. Once services and/or goods are provided to the customer, then these become earned and are transferred to the revenue account with an entry debiting UNEARNED/DEFERRED REVENUES and crediting the REVENUE account.