Quaternary /(?)/

Qua·ter·na·ry

Quaternary

a.
  1. Consisting of four; by fours, or in sets of four.
  2. Later than, or subsequent to, the Tertiary; Post-tertiary; as, the Quaternary age, or Age of man. (Geol.)

Quaternary

n.
  1. The number four.
  2. The Quaternary age, era, or formation. See the Chart of Geology. (Geol.)