What is "azo compound"

n. (context chemistry English) an organic compound of the general formula R-N=N-R¹; they are often coloured and are the basis of many synthetic dyes; a diazene

Azo compounds are compounds bearing the functional group R–N=N–R′, in which R and R′ can be either aryl or alkyl. IUPAC defines azo compounds as: "Derivatives of diazene (diimide), HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene." The more stable derivatives contain two aryl groups. The N=N group is called an azo group. The name azo comes from azote, the French name for nitrogen that is derived from the Greek (a-, "not") + (zōē, life).

Most colored textile and leather articles are treated with azo dyes and pigments.