triplet

UK: /ˈtrɪplɪt/ US: /ˈtrɪplɪt/ ,(trip′lit)

WordReference Random House Learner's Dictionary of American English © 2025

tri•plet /ˈtrɪplɪt/   n. [countable]

1. Medicine one of three offspring born at one birth.
2. any group of three, as three lines of poetry or three musical notes played together.

WordReference Random House Unabridged Dictionary of American English © 2025

tri•plet  (trip′lit), n. 

1. Medicine one of three children or offspring born at the same birth.
2. Medicine triplets, three offspring born at one birth.
3. any group or combination of three.
4. Poetry [Pros.] three successive verses or lines, esp. when rhyming and of the same length;
   a stanza of three lines.
5. Music and Dance Also called tercet. a group of three notes to be performed in the time of two ordinary notes of the same kind.
6. Jewelry an assembled imitation gem with three parts, the center one giving the color, the top and bottom, sometimes genuine, supplying the wearing qualities.
7. Biochemistry, Genetics [Genetics.] a sequence of three nucleotides;
   a codon in messenger RNA and an anticodon in transfer RNA.
8. Optics a compound lens in which three lenses are combined.
9. triplets, (in some card games) three cards of the same denomination.

• triple + -et 1650–60

Collins Concise English Dictionary © HarperCollins Publishers::

triplet / ˈtrɪplɪt/ noun

1. a group or set of three similar things
2. one of three offspring born at one birth
3. a group of three notes played in a time value of two, four, etc
4. a state of a molecule or free radical in which there are two unpaired electrons

Etymology: 17th Century: from triple, on the model of doublet