A Wavedash refers to a type of rapid movement that varies depending on the game where it is performed.
Wavedashing in Tekken Tag Tournament
In Tekken Tag Tournament, a wavedash is performed by successfully linking a crouch dash into another crouch dash. Not only does this technique have the benefit of increased movement speed, but also allows for the automatic parrying of low attacks. This technique gained notoriety for its use on Jin Kazama, Heihachi Mishima, and Kazuya, as not only does the command necessary for performing the wavedash share inputs used by the lightning fast Wave Godfist attack, but the crouch dash itself is necessary for performing the Hell Sweep attack. Attempting to poke a wavedashing character often results in failure due to the Wave Godfist's extreme speed and priority. Attempting to simply block it would result in being tripped by Hell Sweep, while blocking low to block the Hell Sweep would leave the defending player vulnerable to being launched by the Wave Godfist. These factors combined render the wavedash technique almost unpunishable.
Wavedashing in the Capcom games
In some Capcom games, most notably the Marvel vs. Capcom series, a wavedash is a series of short, rapid dashes performed by rapidly alternating between and . This takes advantage of cancelling the slower portion of a normal dash with a crouch, allowing the player to immediately follow up with another dash, resulting in increased speed compared to a normal dash.
Wavedashing in Super Smash Bros. Melee
In Super Smash Bros. Melee, a wavedash is a glitch performed by executing a diagonal downwards airdash the moment the character leaves the ground from a jump. If successful, the wavedash will cause the character to move forward while in their idle standing animation, and is useful for greatly extending the range of certain attacks, most notably grabs. Because each character has different friction constants in Super Smash Bros. Melee, some characters benefit more from wavedashes than others, with low friction characters such as Luigi and Mewtwo gaining a significant benefit from this technique.