ROF

Rate of Fire.
Examples of High ROF weapons are:
Machine-guns, Leech guns, Polarity guns.
Examples of Low ROF weapons are:
Torqueshell Rifles, Rocket Launchers.
Generally high ROF weapons do less damage per hit but hit more often. Weapons with high ROF that features continuous fire like Machine-guns also do not suffer from lag (client-server latency) between shots.