fixed air

noun

Carbon dioxide; carbonic acid.

Ask AI about this wordChatGPTClaudePerplexityGoogle AIGrok

Meanings

nounfixed air (uncountable)
  1. historicaluncountablechemistryCarbon dioxide; carbonic acid.

    Lavoisier then elucidated the exchange of gases in the lungs: the air inhaled was converted into Black's fixed air, whereas the nitrogen (‘azote’) remained unchanged.

    1997, Roy Porter, The Greatest Benefit to Mankind, Folio Society, published 2016, page 246
    1 more example

    The wild gas, the fixed air is plainly broke loose: but we ought to suspend our judgement until […] we see something deeper than the agitation of a troubled and disturbed surface.

    1790, Edmund Burke, Reflections on the Revolution in France, Oxford, published 2009, page 8

Origin

Coined by Scottish chemist Joseph Black in 1756 because it can be absorbed, or fixed, by strong bases.

Full word history & related roots →
Cite this entry
APA

fixed air. (n.d.). In WatkinsX Dictionary. Retrieved November 3, 2026, from https://dictionary.watkinsx.com/word/fixed%20air

MLA

“fixed air.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/fixed%20air. Accessed November 3, 2026.

Chicago

WatkinsX Dictionary, s.v. “fixed air,” accessed November 3, 2026, https://dictionary.watkinsx.com/word/fixed%20air.

Source: fixed air on Wiktionary, CC BY-SA 4.0.