CO₂

• CO2 (nonstandard; acceptable when subscripts are not available or cannot be displayed)

CO₂

1. Carbon dioxide.

• IPA^(key): /si.oʊ.tu/, /siː.əʊ.tuː/

CO₂ (uncountable)

1. carbon dioxide.
   • 2009 April 9, Office of the Press Secretary, “President Obama Announces Accelerated Purchase of 17,600 New American Vehicles for Government Fleet”, in White House‎^[1], archived from the original on 10 March 2010:

     By swapping out less efficient federal vehicles for new hybrid and fuel efficient ones, this strategy will reduce gasoline consumption by 1.3 million gallons per year and prevent 26 million pounds of CO₂ from entering the atmosphere.

   • 2025 February 19, Christian Wolmar, “Reeves talks of 'growth' but pays lip service to the railway”, in RAIL, number 1029, page 35:

     On aviation, the Chancellor seemed to suggest it was open season for expanding airports across the UK, irrespective of the fact that flying is a major source of CO² in the atmosphere.

Be sure to capitalize the O, or else it would mean a diatomic molecule of cobalt.

• carbon dioxide
• carbonic acid gas

• O. C., O.C., OC, Oc, Oc.

From translingual CO₂.

• IPA^(key): /seotoːˀ/, [seoˈtˢoˀ]

CO₂ c (singular definite CO₂'en, not used in plural form)

1. (inorganic chemistry) carbon dioxide

   Synonyms: carbondioxid, kuldioxid, kultveilte

From translingual CO₂.

• IPA^(key): /ˌt͡seːoˈt͡svaɪ̯/

• Audio:

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CO₂ n (strong, genitive CO₂, no plural)

1. (inorganic chemistry) carbon dioxide

   Synonyms: Kohlendioxid, Kohlenstoffdioxid