adj. of, like, or impregnated with nitrogen, esp. in the tervalent state. nitrous acid a weak acid existing only in solution and in the gas phase. °Chem. formula: HNO
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. nitrous oxide a colourless gas used as an anaesthetic (= laughing-gas) and as an aerosol propellant. °Chem. formula: N
[ 2 ]
O.
[ L nitrosus (as NITRE), partly through F nitreux ]