Source : Free On-Line Dictionary of Computing

Programmable Read-Only Memory
     
         (PROM) A kind of {ROM} which can be written using a
        PROM programmer.  The contents of each bit is determined by a
        {fuse} or {antifuse}.  The memory can be programmed once after
        manufacturing by "blowing" the fuses, which is an irreversible
        process.  Blowing a fuse opens a connection while blowing an
        antifuse closes a connection (hence the name).  Programming is
        done by applying high-voltage pulses which are not encountered
        during normal operation.
     
        (1995-04-22)