'ammonite' originates from the Latin word 'ammonis cornu', meaning 'horn of Ammon', referring to the Egyptian god Ammon, who was often depicted with ram's horns.

'ammonis cornu' transformed into the French word 'ammonite', and eventually became the modern English word 'ammonite'.

Initially, it referred to the 'horn of Ammon', but over time it evolved into its current meaning of 'extinct marine mollusks'.