quadruplet
(noun)
noun
1. the cardinal number that is the sum of three and one
Similar word(s): four, foursome, quartet, quaternary, quaternion, quaternity, tetrad
Definition categories: quantity, digit, figure
2. one of four children born at the same time from the same pregnancy
Similar word(s): quad
Definition categories: person, sib, sibling
3. a set of four similar things considered as a unit