Electrically Programmable ROM.
Higher than normal voltages are required to program (save information) to this kind of ROM.
Typically a large IC with a paper sticker covering a little glass window.
The memory can be reset or cleared with ultra-violet light.
The robot worked fine until it's uncovered EPROMs were exposed to sunshine.
People who do not attend prom that join an internet chat room during their prom.
Joe: Hey man did you go to prom?
Bob: nah ... I went to eprom .. it was awesome I saw all the cool people on!