A customer deposit could be an amount paid by a customer to a company prior to the company providing it with goods or services. In other words, the company receives the money prior to earning it. The company receiving the money has an obligation to provide the goods or services to the customer or to return the money.
For example, Ace Manufacturing Co. might agree to produce an expensive, custom-made machine for one of its customers. Ace requires that the customer pay $50,000 before Ace begins to design and construct the machine. The $50,000 payment is made in December 2012 and the machine must be finished by June 30, 2013. The $50,000 is a down payment toward the machine's price of $400,000.
In December 2012, Ace will debit Cash for $50,000 and will credit Customer Deposits, a current liability account. (The customer will record the $50,000 payment with a debit to a long-term asset account such as Construction Work in Progress or Downpayment on New Equipment, and will credit Cash.)