氮氧化物 dànyǎnghuàwù nitrogen oxide Origin Definitions Defs Strokes Stroke Words Sentences Sents 氮 dàn noun nitrogen the nonmetallic chemical element with symbol N; a colorless, odorless gas that makes up about four-fifths of the earth's atmosphere氧化物 yǎnghuàwù oxide a chemical compound consisting of oxygen combined with another element or group