My emphasis. Is that your definition? That it's impossible to write to an EPROM in a computer? Sorry, it's possible. Just open the case, flash it with the right frequency of UV for 10-20 minutes (or leave it outside in the sun for several weeks), stick electrodes on the pins and push some voltage. Tada, it's written. Not that I'd want to do that, but it is possible.
No, the silly thing is to call an EPROM a ROM just because it's sitting in a computer case. BTW, you didn't answer. If I break out the superglue, is my USB key EEPROM now a ROM?