noun
quadruplet
kwah-DROO-plit/kwɑːˈdruːplət/
A set of four related units.
The four newborn siblings form a quadruplet beside their recovering mother.

Etymology
The “fourfold” base was given the ending of triplet to name one of four children born together. The ending links the word to a birth group, rather than simply to an amount multiplied by four.
In context
four sets of quadruplet
More examples
- The code stores each point as a quadruplet of numbers.
- All four quadruplets celebrate their birthday together.
- The drummer plays a quadruplet in the space of three beats.
Forms
quadruplet · quadruplets
quadruple verb — To make four times as large.
Similar words
- quartet
- Quartet often refers to four performers or their music.
- foursome
- Foursome usually means four people doing an activity together.