'fusiform' originates from Latin, specifically from Late Latin 'fusiformis', where 'fusus' meant 'spindle' and '-formis' (from 'forma') meant 'shape or form'.

'fusiformis' in Late Latin/Medieval Latin passed into English as 'fusiform' via scientific and medical Latin usage in the 17th–18th centuries, becoming established in modern English with the same form.

Initially it meant 'having the form of a spindle' and over time has retained that core meaning, being applied in general and technical contexts to describe spindle-shaped objects or structures.