A collection or combination of three of a kind; three united.
- A group or set of three of one kind.
- One of three children born at one birth.
- A group of three lines of verse.
- Music A group of three notes having the time value of two notes of the same kind. Also called tercet.
- Physics A multiplet with three components.
- Genetics A unit of three successive nucleotides in a molecule of DNA or RNA that codes for a specific amino acid; a codon or anticodon.