What is "azo-"

Azo- \Az"o-\ [See Azote.] (Chem.) A combining form of azote;

1. Applied loosely to compounds having nitrogen variously combined, as in cyanides, nitrates, etc.

2. Now especially applied to compounds containing a two atom nitrogen group uniting two hydrocarbon radicals, as in azobenzene, azobenzoic, etc. These compounds furnish many artificial dyes. See Diazo-.

word-forming element denoting the presence of nitrogen, 1879, from comb. form of azote, the old term for "nitrogen" (from Greek a- "not, without" (see a- (3)) + zoion "a living being;" see zoo); coined in French by Lavoisier & de Morveau because living things cannot survive in the gas.

pre. 1 (context chemistry English) containing nitrogen 2 (context organic chemistry English) Having a bivalent azo group (-N=N-) as a substituent