quaternary

[ kwot-er-ner-ee, kwuh-tur-nuh-ree ]

adjective

1. consisting of four.
2. arranged in fours.
3. (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.
4. Metallurgy. (of an alloy) having four principal constituents.

noun

, plural quat·er·nar·ies.

1. a group of four.
2. the number four.
3. (initial capital letter) Geology. the Quaternary Period or System.

quaternary

¹

/ kwəˈtɜːnərɪ /

adjective

1. consisting of fours or by fours
2. fourth in a series
3. chem containing or being an atom bound to four other atoms or groups

   a quaternary ammonium compound

4. maths having four variables

noun

1. the number four or a set of four

Quaternary

²

/ kwəˈtɜːnərɪ /

adjective

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

noun

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

quaternary

/ kwŏt′ər-nĕr′ē /

Noun

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.
2. See Chart at geologic time

Adjective

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.

Word History and Origins

Origin of quaternary¹

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

Word History and Origins

Origin of quaternary¹

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

Example Sentences

It's tough, however, to make these molecules if they require a quaternary carbon -- a carbon atom bonded to four other carbon atoms.

From Science Daily

They identified chemicals that selectively damaged oligodendrocytes belong to two classes: organophosphate flame retardants and quaternary ammonium compounds.

From Science Daily

The Salyerses’ unusual marriage is known as a quaternary marriage, and their sons are known as quaternary twins.

From Washington Post

There are long-term risks associated with the overuse of certain disinfectants, such as quaternary ammonium compounds.

From New York Times

Two disinfectants known to be sprayed at Glades are called Mint and Maxim Neutral, and their ingredients that have raised concern are known as quaternary ammonium compounds, or QACs.

From Scientific American