An Outrun is a term taken from the herding world and describes a pattern where a dog takes a rounded path to a distant target.
Some dogs have a natural Outrun, Border Collies and herding breeds in particular, but all dogs can be taught the skill.
Dogs often have an unbalanced Outrun. One of the directions, clock or counter may be difficult for your dog.
An Outrun is beneficial in that it gives the handler time to throw and gives the dog a better angle of approach. Outruns create natural Interceptions.
Outruns are different than a Working Flank
The Working Flank is a moving position. On a Working Flank the dog is out to your side some distance and holds position, moving with you as you move around the field. The..., as the dog is flanking to a target and not working with the handler.