'balneologist' originates from New Latin/Modern Latin and Greek, specifically the word 'balneologia' (formed from Latin 'balneum' and Greek 'logia'), where 'balneum' meant 'bath' and 'logia' meant 'study'; English formed the agent noun with the suffix '-ist'.

'balneologist' developed from the New Latin term 'balneologia' (meaning 'study of baths') and entered English usage in the 19th century by adding the agent suffix '-ist' to form the practitioner term.

Initially, related terms referred primarily to the study of baths and bathing ('study of baths'); over time the English form 'balneologist' came to refer specifically to a practitioner or specialist in therapeutic bathing and spa treatments.