i.e. Number of days a firm's cash remains tied up

http://bluepointstrategies.com/uploads/White_Paper_-_The_Cas...
Cash Conversion Cycle = Days Sales Outstanding + Inventory Days Outstanding - Payables Days Outstanding

http://bluepointstrategies.com/uploads/White_Paper_-_The_Cas...
The cash conversion cycle is the number of days negotiated financing is needed to support the operating cycle of a business. A business’s operating cycle is simply the number of days its goods are tied up in inventory plus the number of days its sales are tied up in receivables.

http://www.streetdirectory.com/travel_guide/174/business_and...
The cash conversion cycle is simply the duration of time it takes a firm to convert its activities requiring cash back into cash returns. The cycle is composed of the three main working capital components: Accounts Receivable outstanding in days (ARO), Accounts Payable outstanding in days (APO) and Inventory in days (IOD). The Cash Conversion Cycle (CCC) is equal to the time is takes to sell inventory and collect receivables less the time it takes to pay your payables

http://www.finance-lib.com/financial-term-number-of-days-sal...
NUMBER OF DAYS SALES IN RECEIVABLES
(also called average collection period). The number of days of net sales that are tied up in credit sales (accounts receivable) that haven’t been collected yet.