[ kwot-er-ner-ee, kwuh-tur-nuh-ree ]
See synonyms for: quaternaryquaternaries on Thesaurus.com

  1. consisting of four.

  2. arranged in fours.

  1. (initial capital letter)Geology. noting or pertaining to the present period of earth history, forming the latter part of the Cenozoic Era, originating about 2 million years ago and including the Recent and Pleistocene Epochs.

  2. Metallurgy. (of an alloy) having four principal constituents.

noun,plural quat·er·nar·ies.
  1. a group of four.

  2. the number four.

  1. (initial capital letter)Geology. the Quaternary Period or System.

Origin of quaternary

1400–50; late Middle English <Latin quaternārius consisting of four, equivalent to quatern(ī) four at a time + -ārius-ary

Words Nearby quaternary

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2024

How to use quaternary in a sentence

  • The Post-tertiary or quaternary division comprises the concluding chapters of geological history.

    Geology | James Geikie

British Dictionary definitions for quaternary (1 of 2)


/ (kwəˈtɜːnərɪ) /

  1. consisting of fours or by fours

  2. fourth in a series

  1. chem containing or being an atom bound to four other atoms or groups: a quaternary ammonium compound

  2. maths having four variables

nounplural -naries
  1. the number four or a set of four

Origin of quaternary

C15: from Latin quaternārius each containing four, from quaternī by fours, distributive of quattuor four

British Dictionary definitions for Quaternary (2 of 2)


/ (kwəˈtɜːnərɪ) /

  1. of, denoting, or formed in the most recent period of geological time, which succeeded the Tertiary period nearly two million years ago

  1. the Quaternary the Quaternary period or rock system, divided into Pleistocene and Holocene (Recent) epochs or series

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for quaternary


[ kwŏtər-nĕr′ē ]

  1. Quaternary. The second and last period of the Cenozoic Era, from about 2 million years ago to the present. During this time the continents were situated approximately as they are today, although the geography was different due to fluctuations in sea levels caused by the advance and retreat of ice sheets. Humans first appeared during this period. See Chart at geologic time.

  1. Relating to or having a carbon atom that is attached to four other carbon atoms in a molecule. Quaternary pentane, for example, contains five carbon atoms of which one is in the center and the other four are each attached to it.

The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.