or laughing gas
Inorganic compound, one of the oxide s of nitrogen .
A colourless gas with a pleasantly sweetish odour and taste, it has an analgesic effect when inhaled; it is used as an anesthetic (often called just "gas") in dentistry and surgery. This effect is preceded by mild hysteria, sometimes with laughter, hence the name laughing gas . It is also used as a propellant in food aerosols and as a leak detector.