WordWeb Online

1. Consisting of or especially arranged in sets of four
   "a quaternary compound"
   - quaternate
    
2. 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"
   - fourth, 4th

1. The cardinal number that is the sum of three and one
   - four, 4, IV, tetrad, quatern, quaternion, quaternity, quartet, quadruplet, foursome, Little Joe

1. Last 2 million years
   - Quaternary period, Age of Man

Derived forms: quaternaries

See also: multiple, ordinal

Type of: digit, figure, geological period, period

Part of: Age of Mammals, Cenozoic, Cenozoic era

Encyclopedia: Quaternary