The corna (Italian for horns, also mano cornuta, horned hand) is a gesture with a vulgar meaning in Mediterranean countries. Its origins can be traced to Ancient Greece. It is realized by stretching the index and little fingers while holding the middle and ring fingers down with the thumb.
Corna（意大利语中的“角”一词，也写作mano cornuta或是horned hand）原是一种在地中海沿岸国家的居民用的一种下流的手势。其起源可追溯至古希腊时期。此手势将食指与小指伸直，与此同时要用拇指压住弯下的中指和无名指。
The same gesture is used for warding off bad luck or the evil eye. It is also used as a reference to Satan and Satanism, at least since the 1960s, and has a variety of meanings in heavy metal, where it is also known as devil horns, goat horns, rock horns, throwing the goat, evil fingers, Pommesgabel, mano cornuto, peka evil or just the horns.There is a theory that states that Corna is the antagonist of the Sign of the Cross- where three fingers brought to a point symbolize the Holy Trinity. Opposite of the Holy Trinity is the Unholy Trinity: Satan, Antichrist and the False Prophet, represented by the three fingers of the Corna.
The same gesture is known as Rock on in some U.S. rock music subcultures, and Hook 'em Horns when used by supporters of The University of Texas or its sports teams. In that context, it is used to approximate the shape of the horns of a Texas longhorn steer. Neither use is considered vulgar or Satanistic.
The corna is not to be confused as the sign for "I love you" in American Sign Language, which is made by also extending the thumb, or the shaka sign used in Hawaii, which is made by extending just the thumb and little finger.
With the advent of e-mail and other forms of electronic text-based communications; the backslash, lower case "m", and forward slash characters are used as a representation: \m/