- quaternate, quaternary - consisting of or especially arranged in sets of four; "quaternate leaves"; "a quaternary compound"
Antonym: single (indirect, via multiple)
- fourth, 4th, quaternary - coming next after the third and just before the fifth in position or time or degree or magnitude; "the quaternary period of geologic time extends from the end of the tertiary period to the present"
Antonym: cardinal (indirect, via ordinal)
- Quaternary, Quaternary period, Age of Man - last 2 million years
--1 is a kind of period, geological period
--1 is a part of Cenozoic, Cenozoic era, Age of Mammals
--1 has parts:Holocene, Holocene epoch, Recent epoch; Pleistocene, Pleistocene epoch, Glacial epoch - four, 4, IV, tetrad, quatern, quaternion, quaternary, quaternity, quartet, quadruplet, foursome, Little Joe - the cardinal number that is the sum of three and one
--2 is a kind of digit, figure