'ammonoid' originates from the Greek word 'Ammon,' referring to the Egyptian god Ammon, whose horns the shells of these creatures resemble.

'Ammon' transformed into the Latin word 'Ammonis,' and eventually became the modern English word 'ammonoid.'

Initially, it referred to the resemblance of the shell to the horns of Ammon, but over time it evolved into its current meaning of a group of extinct marine mollusks.