last 2 million years

[ Syn: quaternary , quaternary period , age of man ]

the cardinal number that is the sum of three and one

[ Syn: four , 4 , iv , tetrad , quatern , quaternion , quaternity , quartet , quadruplet , foursome , little joe ]

consisting of or especially arranged in sets of four; quaternate leaves; a quaternary compound

[ Syn: quaternate ]

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

[ Syn: fourth , 4th ]