qua·ter·na·ry
ˈkwä-tər-ˌner-ē 
ˈkwä-tə-,
kwə-ˈtər-nə-rē
1
a
: 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
plural quaternaries
1
capitalized
: the Quaternary period or system of rocks
2
: a member of a group fourth in order or rank
Examples of quaternary in a Sentence
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Alexis Kayser, MSNBC Newsweek, 16 May 2025
Tenet Healthcare offers tertiary (specialized) care such as cardiothoracic surgery, complex spinal surgery, neonatal intensive care and neurosurgery, along with quaternary care (a higher level of specialized care).
—Charles Rotblut, Forbes, 12 Dec. 2024
Joseph Truini, Popular Mechanics, 6 June 2017
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Adjective
At Providence Swedish, an urban, tertiary and quaternary medical facility, her patients can easily access diabetes education, genetic and nutrition counseling.
—Alexis Kayser, MSNBC Newsweek, 16 May 2025
Tenet Healthcare offers tertiary (specialized) care such as cardiothoracic surgery, complex spinal surgery, neonatal intensive care and neurosurgery, along with quaternary care (a higher level of specialized care).
—Charles Rotblut, Forbes, 12 Dec. 2024
Noun
Today's PT lumber is treated with safer, less toxic chemicals, such as alkaline copper quaternary (ACQ) or copper azole.
—Joseph Truini, Popular Mechanics, 6 June 2017
See All Example Sentences for quaternary
Cite this Entry
“Quaternary.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/quaternary. Accessed 30 May. 2025.
Copy CitationMedical Definition
quaternary
1 of 2 adjective
qua·ter·na·ry
ˈkwät-ə(r)-ˌner-ē
kwə-ˈtər-nə-rē
kwə-ˈtər-nə-rē
: consisting of, containing, or being an atom bonded to four other atoms
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