PROM

Acronym of programmable read-only memory, a chip that can be programmed one or more times (depending on the type) and generally cannot be re-programmed without special equipment (if at all); once programmed and installed in a device, it functions as a read-only chip (as if it had been hard-wired to function that way).

Initialism of prelabor rupture of membranes.

Initialism of passive range of motion.