nitrous oxide(redirected from N2o)
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laughing gas, one of the oxides of nitrogen. It is used as medicine in a mixture with oxygen to induce inhalation narcosis in surgical operations and childbirth, and sometimes in myocardial infarction. It was called laughing gas by the English chemist H. Davy, who, while experimenting on himself to study the effect of nitrous oxide (1799), observed excitation in the initial phase, accompanied by laughter and chaotic body movements, and, in the following phase, unconsciousness.