ALT: [ælt] [ôlt]
1. The first octave above the treble staff.
2. The choice between two mutually exclusive possibilities.
3. A key on a keyboard that when pressed at the same time as another key gives the second key an alternative function.
4.An alternate character, often referred to in slang as alt, alt char, or less commonly multi, is a character in addition to one's "primary" or "Main" player character. Players are generally not secretive about their alternate characters, unless having multiple characters is illegal, or in a role-playing environment where alternate characters might be judged by the actions of the primary character.