unearned revenue

When an individual or company receives money for a service or product that has yet to be fulfilled.

Investopedia Says:
For example, prepayment on a lease contract - the revenue is a liability until it has been earned.

1. Payment received in advance of providing a good or service. Since an obligation exists on the part of the company to provide goods or services for which the advance payment was received, unearned revenue is a liability. An example is a retainer received by an attorney. When the services are performed, revenue is then earned.

2. In taxation, revenue obtained other than from personal services.

The noun has 2 meanings:

Meaning #1: (taxes) personal income that you did not earn (e.g., dividends or interest or rent income)
  Synonym: unearned income

Meaning #2: (accounting) income received but not yet earned (usually considered a current liability on a company's balance sheet)
  Synonym: unearned income