quaternary

qua·ter·nar·y  (kwtr-nr, kw-tûrn-r)

adj.

1. Consisting of four; in fours.

2. Quaternary Of or belonging to the geologic time, system of rocks, or sedimentary deposits of the second period of the Cenozoic Era, from the end of the Tertiary Period through the present, characterized by the appearance and development of humans and including the Pleistocene and Holocene epochs. See Table at geologic time.

3. Chemistry Relating to an atom bonded to four carbon atoms: a quarternary nitrogen atom.

n. pl. qua·ter·nar·ies

1. The number four.

2. The member of a group that is fourth in order.

3. Quaternary The Quaternary Period or its system of deposits.

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[Latin quaternrius, from quatern, by fours, from quater, four times; see k^wetwer- in Indo-European roots.]

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quaternary

Adjective

consisting of four parts [Latin quaterni by fours]

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Quaternary

Adjective

Geol of the most recent period of geological time, which started about one million years ago

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quaternary  (kwtr-nr)

Noun

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.

Adjective

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.

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Quaternary four things collectively; a group of four facts or circumstances. Also quaternion.

Examples: quaternion of earth, air, water, and fire, 1695; of English writers—Shakespeare, Hooker, Bacon, Jeremy Taylor, 1868; of topics, 1648.

Thesaurus

Noun	1.	Quaternary - last 2 million years                 Age of Man, Quaternary period Age of Mammals, Cenozoic, Cenozoic era - approximately the last 63 million years Holocene, Holocene epoch, Recent, Recent epoch - approximately the last 10,000 years Pleistocene, Pleistocene epoch, Glacial epoch - from two million to 11 thousand years ago; extensive glaciation of the northern hemisphere; the time of human evolution
	2.	quaternary - the cardinal number that is the sum of three and one IV, Little Joe, quadruplet, quartet, quatern, quaternion, quaternity, tetrad, 4, four, foursome digit, figure - one of the elements that collectively form a system of numeration; "0 and 1 are digits"
Adj.	1.	quaternary - consisting of or especially arranged in sets of four; "quaternate leaves"; "a quaternary compound" quaternate multiple - having or involving or consisting of more than one part or entity or individual; "multiple birth"; "multiple ownership"; "made multiple copies of the speech"; "his multiple achievements in public life"; "her multiple personalities"; "a pineapple is a multiple fruit"
	2.	quaternary - 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" 4th, fourth ordinal - being or denoting a numerical order in a series; "ordinal numbers"; "held an ordinal rank of seventh"