Ma'anar ƙamus na "nitrogen fixation" shine tsarin da iskar iskar nitrogen daga sararin samaniya ke juyar da ita zuwa wani nau'i wanda kwayoyin halitta zasu iya amfani da su, kamar ammonia ko nitrates. Wannan tsari yana iya faruwa ta dabi'a ta hanyar wasu kwayoyin cuta, ko kuma ana iya sauƙaƙe ta ta hanyar sa hannun ɗan adam, kamar amfani da takin nitrogen a cikin aikin gona. Gyaran Nitrogen yana da mahimmanci don girma da kuma rayuwa na tsire-tsire da yawa da sauran halittu masu rai, saboda nitrogen wani muhimmin sashi ne na yawancin kwayoyin halitta, ciki har da sunadarai da acid nucleic.