In all Fighting Games, each attack you do has a lag time or recovery; the amount of time after you make that attack that you cannot make another attack. After you throw a punch, there may be a second or two wherein you cannot throw another punch, to stop you from just hammering the punch button and throwing out fifteen punches per second. These recovery-shortening actions are known as canceling. Of course, in real examples the time is much shorter. This trope is almost completely ubiquitous in Fighting Games, though is by no means exclusive to them.