'atrazine' originates from modern chemical nomenclature (New Latin/International), specifically from the word 'triazine', where 'tri-' meant 'three' and '-azine' referred to nitrogen-containing heterocycles (the element name nitrogen comes via French 'azote').

'atrazine' developed as a chemical/trade name in 20th-century organic chemistry derived from the parent ring name 'triazine' and the specific substituents on that ring; the plural form 'atrazines' naturally followed usage to refer to multiple related compounds or residues.

Initially it named a molecular structure (a triazine ring with particular substituents); over time it came to denote the commercial herbicide(s) themselves and, in environmental contexts, residues or classes of related compounds.