Hitbox

A hitbox is a term used in fighting games to refer to an area of a character that is programmed to react to contact with another character or one of their attacks.

Description
Every character has hitboxes that fall into at least one of the following two categories: "attacking" and "vulnerable", the location of which vary with the moves they perform.

Priority
Priority is a term used by fighting game players to quantify the ability of a given move to beat another move when the two are used against each other. The priority of a move(s) is not quantified in-game, and is instead based on the move's hitboxes. When a move is stated to have high priority over another move, it means that the character's "attacking" hitbox will be the first to make contact with the target's "vulnerable" hitbox more often than not.

The Shoryuken is a prime example of a high-priority move; during the rising uppercut, the user's "attacking" hitboxes cover most of their body, and they do not become vulnerable until their descent.