diazonium
noun
di·a·zo·ni·um ˌdī-ə-ˈzō-nē-əm 
: the monovalent cation N2+ that is composed of two nitrogen atoms united to carbon in an organic radical and that usually exists in salts used in the manufacture of azo dyes
Word History
Etymology
International Scientific Vocabulary di- + az- + -onium
First Known Use
1895, in the meaning defined above
Medical Definition
diazonium
noun
di·a·zo·ni·um ˌdī-ə-ˈzō-nē-əm
: the monovalent cation N2+ that is composed of two nitrogen atoms united to carbon in an organic radical and that usually exists in salts used in the manufacture of azo dyes