Damage per second
Damage per second (DPS) is a measure of damage dealt over one second.
 Types of DPS
 Burst DPS
 Sustained DPS
Sustained DPS refers to DPS dealt over an extended period of time. Also known as damage over time, or damage dealt over a period of time. High sustained damage is the preferable form of damage against targets with relatively high health. Often referred to as pressure in PvP.
 Calculation of average DPS
Max sword (any type), 15-22 damage, 1.3 speed (whereas 15="minimum max damage" and 22 being "maximum max damage")
And how to calculate DPS for a max damage sword:
First, calculate the average damage per hit: 15 (minimum damage) + 22 (maximum damage) = 37. 37/2 = 18.5 average damage
This is how much damage the weapon averages per hit. To figure the average damage per second, divide it by attack speed.
18.5 (damage)/1.3 (seconds) = 13.875 damage/second
This would come out to, 13.875 average DPS.
In reality, there are other factors, such as critical hits and armor rating as well as attack skills, which make the calculation of mean damage per attack complicated. Please note this is "average" DPS, actual performance will vary for a weapon with different minimum and maximum damages.