triplet

American  

[trip-lit] / ˈtrɪp lɪt /

noun

1. one of three children or offspring born at the same birth.

2. triplets, three offspring born at one birth.

3. any group or combination of three.

4. Prosody. three successive verses or lines, especially when rhyming and of the same length; a stanza of three lines.

5. Also called tercet.  Music. a group of three notes to be performed in the time of two ordinary notes of the same kind.

6. an assembled imitation gem with three parts, the center one giving the color, the top and bottom, sometimes genuine, supplying the wearing qualities.

7. 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.

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triplet British  

/ ˈtrɪplɪt /

noun

1. a group or set of three similar things

2. one of three offspring born at one birth

3. music a group of three notes played in a time value of two, four, etc

4. chem a state of a molecule or free radical in which there are two unpaired electrons

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Etymology

Origin of triplet

First recorded in 1650–60; triple + -et

Explanation

When a mammal gives birth to three offspring at the same time, each is a triplet. If you're a triplet, you've got at least two siblings right from the moment you're born. While some triplets are identical (three fetuses from a single egg), it's more likely for triplets to be fraternal (from three separate eggs). In humans, twins are more common than triplets, and multiple births of more than three are even more rare. Triplet can also mean another group of three, like three lines of poetry or three notes of music.

Example Sentences

Other potential triplet superconductors require temperatures close to 1K, making 7K far more practical and attainable.

From Science Daily • Feb. 21, 2026

"The key to the quenching mechanism lies in how quickly and efficiently the triplet states can be deactivated," said Alessandro Agostini, researcher at the University of Padua, Italy and co-lead author of the study.

From Science Daily • Oct. 22, 2025

Under too much light, though, chlorophyll can enter a dangerous "triplet" state, producing reactive oxygen molecules that can damage cells.

From Science Daily • Oct. 22, 2025

But there’s one in particular … it’s one where Lucero, a big pop star in Mexico, plays three versions of herself, so she’s a triplet.

From Los Angeles Times • Oct. 13, 2025

At first, one triplet seemed to overlap with another—making the prospect of a simple code impossible.

From "The Gene" by Siddhartha Mukherjee

Related Words

• threesome
• trilogy
• triumvirate