Third

Third or 3rd may refer to:

Numbers

Interval number of three in a musical interval
- major third, a third spanning four semitones
- minor third, a third encompassing three half steps, or semitones
- neutral third, wider than a minor third but narrower than a major third
- augmented third, an interval of five semitones
- diminished third, produced by narrowing a minor third by a chromatic semitone
Third (chord), chord member a third above the root
Degree (music), three away from tonic
- mediant, third degree of the diatonic scale
- submediant, sixth degree of the diatonic scale – three steps below the tonic
- chromatic mediant, chromatic relationship by thirds
ladder of thirds, similar to the circle of fifths

Third (play), a 2005 work by Wendy Wasserstein
Third (curling), a curling position
Thirds, third-born children in the 1985 novel Ender's Game
Third World, economically underdeveloped nations
Third-class degree, type of British undergraduate degree classification
Third (angle), in astronomy and cartography, a 60th of a second, a 3600th of a minute, a 216,000th of a degree