Which term describes a type of memory that retains data even when the power is off?

The term that describes a type of memory that retains data even when the power is off is ROM, which stands for Read-Only Memory. Unlike volatile memory such as RAM, which loses its contents when the power is turned off, ROM is non-volatile. This means that the data stored in ROM remains intact irrespective of the power state. ROM is typically used to store firmware or software that is not intended to be modified frequently, such as the computer's BIOS, which is essential for booting up the system and performing hardware checks.

In contrast, RAM is temporary storage used for data that a computer is actively using; it requires power to maintain its data. Cache memory also serves a similar purpose as RAM but is optimized for high-speed data access. Flash memory, while also non-volatile, is more often associated with storage devices like USB drives and solid-state drives rather than the traditional definition of ROM.