quaternary Meaning, Definition & Usage

  1. noun last 2 million years
    Quaternary period; Age of Man.
  2. noun the cardinal number that is the sum of three and one
    tetrad; quaternity; quadruplet; foursome; Little Joe; IV; four; quaternion; quatern; quartet; 4.
  3. adjective satellite consisting of or especially arranged in sets of four
    quaternate.
    • quaternate leaves
    • a quaternary compound
  4. adjective satellite coming next after the third and just before the fifth in position or time or degree or magnitude
    4th; fourth.
    • the quaternary period of geologic time extends from the end of the tertiary period to the present

WordNet

Qua*ter"na*ry adjective
Etymology
L. quaternarius consisting of four each, containing four, fr. quaterni four each, fr. quattuor four: cf. F. quaternaire. See Four.
Definitions
  1. Consisting of four; by fours, or in sets of four.
  2. (Geol.) Later than, or subsequent to, the Tertiary; Post-tertiary; as, the Quaternary age, or Age of man.
Qua*ter"na*ry noun
Etymology
L. numerus quaternarius: cf. F. quaternaire.
Definitions
  1. The number four. Boyle.
  2. (Geol.) The Quaternary age, era, or formation. See the Chart of Geology.

Webster 1913