1. A resource that is used up during a process, that is not part of the finished product. 2. Accounting: An expenditure or cost that (1) is related to either a specific operation or to the entire firm, (2) does not go on to become an important component of the merchandise and services offered, and (3) has no direct relationship to a particular output. 3. Data communications: The addition of data bits to data that is transmitted by the user, which aids in the transmission of information and sending out instructions related to the operations. 4. Utilities: The loss of energy or water incurred during the transmission of power from the power production plant to the house of the consumer.