An ability in many Final Fantasy games. Usually it restores HP to all currently fighting members of your party, but it can do so in different ways.
In Final Fantasy VII, for example, White Wind restores to each party member HP equal to the difference between the caster's current HP and his/her max HP. In Final Fantasy X, however, it works differently, because IIRC it restores each of the 3 active party members to full health.
Also, in most games it is received from an enemy, whether as a Blue magic, by using Gau or Strago, by having an Enemy Skill materia equipped, by getting an item to teach Quistis White Wind, by Cooking something, or by Lancet-ing certain enemies with Kimahri.