quaternary

1 of 2

adjective

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

quaternary

2 of 2

noun

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

Recent Examples on the Web

Adjective

Thus, an atom of silver holds a distinctly different quaternary imprint compared to one of gold. —Pravir Malik, Forbes.com, 10 July 2025

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

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

Word History

Etymology

Adjective

Latin quaternarius, from quaterni four each

First Known Use

Adjective

1605, in the meaning defined at sense 1a

Noun

1880, in the meaning defined at sense 1

Phrases Containing quaternary

• quaternary ammonium compound

Rhymes for quaternary

• accessary
• adversary
• ancillary
• arbitrary
• aviary
• axillary
• beriberi
• breviary
• budgetary
• capillary
• catenary
• cautionary

Kids Definition

Quaternary

adjective

Qua·​ter·​na·​ry

ˈkwät-ə(r)-ˌner-ē,

kwə-ˈtər-nə-rē

: of, relating to, or being the period of geological history from the end of the Tertiary period to the present time or the corresponding system of rocks see geologic time

Quaternary noun

Medical Definition

quaternary

1 of 2 adjective

qua·​ter·​na·​ry ˈkwät-ə(r)-ˌner-ē  kwə-ˈtər-nə-rē 

: consisting of, containing, or being an atom bonded to four other atoms

quaternary

2 of 2 noun

plural quaternaries

: quaternary ammonium compound