Azo-

1. 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-.
2. A combining form of azote
3. Applied loosely to compounds having nitrogen variously combined, as in cyanides, nitrates, etc.

The word meanings were obtained from OPTED(The Online Plain Text English Dictionary), which is based on “The Project Gutenberg Etext of Webster’s Unabridged Dictionary” which is in turn based on the 1913 US Webster’s Unabridged Dictionary (See Project Gutenburg), as a text file.