'thiazole' originates from New Latin/modern chemical nomenclature, specifically from the combining form 'thio-' (from Greek 'theîon' meaning 'sulfur') and the suffix 'azole' (coined in organic chemistry to denote nitrogen-containing heterocycles), where 'thio-' meant 'sulfur' and 'azole' referred to a nitrogen-containing heterocyclic system.

'thiazole' changed from German 'Thiazol' (and parallel terms in other European chemical literatures of the 19th century) and eventually became the modern English chemical name 'thiazole' (with variant spellings such as 'thiazol' in some languages/contexts).

Initially, it designated the specific parent heterocyclic compound; over time the term broadened to include substituted thiazoles and thiazole-derived functional groups in larger molecules.