- noun the use of a battery to provide power to a volatile device such as a RAM chip to retain data after a computer has been switched off
- noun a battery to provide power to volatile storage devices to retain data after a computer has been switched off
- The use of a battery to power a device or system when the main power fails or is interrupted. For instance, an uninterruptible power supply may provide the power needs of a device through brownouts and blackouts. Also spelled battery back-up.