I just call it a read or a key. You may have heard of an Indian blitz where a corner or a safety blitzes off the edge if they don't have a man to cover.
Some situations will cause an outside linebacker to trade responsibilities with a cornerback or dog, some coaches call CBs that line up on the inside receiver dogs/rovers. If there's not a number two back to your side you can send a blitz off the edge. The blitzing defender can either stretch at a 45 degree angle towards the sideline for contain, scrape towards the QB and play contain 2-3 yards deep in the backfield, scrape the edge and stay flat to pursue behind the offensive line, or their target can be the back shoulder of the player with the ball.
Really depends on the defensive scheme, what the offensive formation is, and what the DC likes.