external memory n. A memo pad, palmtop computer, or written notes. "Hold on while I write that to external memory". The analogy is with store or DRAM versus nonvolatile disk storage on computers.
external memory <storage> A vague term for slower, {non-volatile storage}, usually {magnetic disk}, in contrast to {main memory} which is usually volatile {semiconductor} {RAM}. [{Jargon File}] (1997-02-17)