(initialism) Per calendar month.

(initialism) per cent mille (1000 pcm = 1%)

Initialism of per calendar month: used in lease arrangements, stating that costs are to be paid on a fixed date every month.

Initialism of pulse code modulation. (the system of encoding sound on a telephone for use in the PSTN, using a compander) / Initialism of phase change memory. (a type of non-volatile computer memory)

plural of PCM

(computing) Initialism of Personal Computer Memory Card International Association, a plug and play peripheral device interface, typically for laptop computers.

(computing, humorous, from the above) Initialism of people can't memorize computer industry acronyms.