Proc

A "procedural random occurrence" or "proc" is an effect with a chance of occurring when the trigger condition is met, rather than occurring every time the trigger condition is met. Examples of items with proc bonuses include the "Master of My Domain" and "Luck of the Draw" inscription, Swift Staff Heads and Wand Wrappings of Quickening. Critical hits, daggers' double strikes and most blocking effects are also procs.