quaternary

Meanings

• last 2 million years
• the cardinal number that is the sum of three and one
• consisting of or especially arranged in sets of four
  • "a quaternary compound"
• 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"

Synonyms

4, 4th, Age of Man, four, foursome, fourth, IV, Little Joe, quadruplet, quartet, quatern, Quaternary period, quaternate, quaternion, quaternity, tetrad