DPS is a common term in MMORPGs that stands for "Damage Per Second". It is an average value of how much damage a weapon or ability can do each second, and is derived from dividing the amount of damage done per volley ("DPV") by the recharge time.
For example, if a weapon does 28 Phaser Damage and has a recharge time of 1.5 seconds, its DPS value would be 28 ÷ 1.5, or 18.67 DPS (rounded to 19 DPS in-game).