ARCHAEAN

archean, archaean

(adjective) of or relating to the earliest known rocks formed during the Precambrian Eon

Source: WordNet® 3.1

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Etymology

Noun

archaean (plural archaeans)

(biology) Any organism of the domain Archaea.

Etymology

Adjective

Archaean (not comparable)

(geology) Of, or relating to the geologic eon from about 3,800 to 2,500 million years ago; comprises the Eoarchean, Paleoarchean, Mesoarchean and Neoarchean eras; marked by an atmosphere with little oxygen, the formation of the first continents and oceans and the emergence of simple life.

Proper noun

Archaean

(geology) The eon from 2,500 Ma to 4,000 Ma.

Hypernyms

• (eon 2,500–4,000 Ma): Precambrian

Hyponyms

• (eon 2,500–4,000 Ma): Eoarchaean, Paleoarchaean, Mesoarchaean, Neoarchaean

Coordinate terms

• (eon 2,500–4,000 Ma): Hadean, Proterozoic - eons in Precambrian

Source: Wiktionary

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Ar*chæ"an, a. Etym: [Gr.

Definition: Ancient; pertaining to the earliest period in geological history.

Ar*chæ"an, n. (Geol.)

Definition: The earliest period in geological period, extending up to the Lower Silurian. It includes an Azoic age, previous to the appearance of life, and an Eozoic age, including the earliest forms of life.

Note: This is equivalent to the formerly accepted term Azoic, and to the Eozoic of Dawson.

Source: Webster’s Unabridged Dictionary 1913 Edition

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