'thiamin' originates from modern chemical naming, combining the prefix 'thio-' (from Greek 'theion', meaning 'sulfur') and 'amine' (from 'ammonia' via chemical nomenclature), forming a name for the sulfur-containing amine-like vitamin.

'thiamin' replaced or existed alongside earlier names such as 'aneurin' (from 'anti-' + 'neuritic', reflecting its anti-neuritis activity); the form 'thiamine' became widely used in scientific literature, and 'thiamin' is a common variant spelling.

Initially the name emphasized its chemical groups (a sulfur-containing amine); over time it came to be used primarily to denote the vitamin (vitamin B1) and its nutritional/medical role.