anoxic

American  

[an-ok-sik, uh-nok-] / ænˈɒk sɪk, əˈnɒk- /

adjective

1. containing no oxygen; anaerobic.

   Methanogens are microorganisms that can occur in anoxic sediments, hydrothermal vents, and the intestinal tracts of animals.

2. caused by the absence of oxygen.

   The malpractice suit alleges that the patient’s anoxic brain injury was caused by excessive and improperly dosed medications.

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Etymology

Origin of anoxic

First recorded in 1895–1900; anox(ia) ( def. ) + -ic ( def. )

Example Sentences

"This insight ties evolutionary biology directly to Earth's geochemical history. The archaeal ancestor of eukaryotes began evolving complex features roughly a billion years before oxygen became abundant, in oceans that were entirely anoxic."

From Science Daily • Dec. 6, 2025

There’s no evidence that we’re seeing massive releases of sulfur—although deoxygenation like the Black Sea has experienced, with a larger anoxic zone and die-offs, is a bit of a warning.

From Scientific American • Sep. 26, 2023

At the time, the oceans were anoxic and saturated in dissolved iron.

From Science Magazine • Feb. 15, 2023

Heche suffered a “severe anoxic brain injury” caused by a lack of oxygen, according to a statement released last week on behalf of her family and friends.

From Seattle Times • Aug. 17, 2022

She shook her head at the anoxic list.

From "Anthem of a Reluctant Prophet" by Joanne Proulx