nitrous oxide

 
Pronunciation: /nʌɪtrəsˈɒksʌɪd/

noun

[mass noun]
  • a colourless gas with a sweetish odour, prepared by heating ammonium nitrate. It produces exhilaration or anaesthesia when inhaled and is used (mixed with oxygen) as an anaesthetic and as an aerosol propellant.
    • Chemical formula: N2O