The traditional Vulcan greeting, a raised hand with the fingers parted between the middle and ring fingers, usually accompanied by the words live long and prosper.
The Vulcan salute is made by raising the hand, palm outward, with the fingers parted in a V and the thumb extended. It is offered in greeting and in farewell, with the phrase live long and prosper and the reply peace and long life.
It first appears in Amok Time, exchanged between Spock and T'Pau. Leonard Nimoy devised it, drawing on a gesture of priestly blessing he had seen as a boy in synagogue. Many humans in the stories find it awkward to make.
The salute appears in every era of the franchise. In Star Trek: First Contact the first Vulcan to step onto Earth offers it to Zefram Cochrane, who cannot copy it and shakes hands instead. Spock gives it across the glass to Kirk as he dies in Star Trek II: The Wrath of Khan.