Definition of quaternary
(Entry 1 of 2)
1a
: of, relating to, or consisting of four units or members
b
: of, relating to, or being a number system with a base of four
2
capitalized
: of, relating to, or being the geologic period from the end of the Tertiary to the present time or the corresponding system of rocks — see Geologic Time Table
3
: consisting of, containing, or being an atom bonded to four other atoms
quaternary
noun
plural quaternaries
Definition of quaternary (Entry 2 of 2)
1
capitalized
: the Quaternary period or system of rocks
2
: a member of a group fourth in order or rank
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Merriam-Webster unabridged
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Time Traveler for quaternary
The first known use of quaternary was in 1605
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