ethylenediaminePronunciation: /ˌɛθɪliːndʌɪˈeɪmiːn, -θ(ə)l-, -dʌɪˈam-, -ˈdʌɪəmiːn/Definition of ethylenediamine noun [mass noun] Chemistry a viscous liquid used in making detergents and emulsifying agents. Chemical formula: NH2CH2CH2NH2 ethylenediamine in other Oxford dictionaries Definition of ethylenediamine in the US English dictionary