en Third

Third or 3rd may refer to:

Numbers

3rd, the ordinal form of the cardinal number 3
1⁄3, a fraction of one third
¹⁄₆₀ of a second, i.e., the third in a series of fractional parts in a sexagesimal number system

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
Thirds, a 2007 play by Jacob M. Appel
Third World, economically underdeveloped nations
Third-class degree, a type of British undergraduate degree classification
Third (angle), in astronomy and cartography, fraction of a degree
Richard Third (1927–2016), Anglican bishop in the Church of England
Third Beach, located at Ferguson Point in Stanley Park in Vancouver, British Columbia
Third Brook, flows into West Brook by Walton, New York