'magnesium' originates from New Latin, specifically the word 'magnesium', which ultimately comes from the Greek place-name 'Magnesia' (Magnēsia), associated with certain magnetic stones.

'magnesium' changed from the Greek/Latin place-name 'Magnesia' (referring to a district in Thessaly and its minerals) into Medieval/ New Latin forms such as 'magnesia' and 'magnesium', and eventually became the modern English word 'magnesium'.

Initially, it referred to stones or minerals from 'Magnesia' (and related magnetic minerals); over time the term came to denote the metallic element now called 'magnesium'.