'acanthodii' originates from Greek, specifically the word 'akantha,' where 'akantha' meant 'thorn' or 'spine.'

'Acanthodii' changed from the Greek word 'akanthodes' and eventually became the modern English word 'acanthodii.'

Initially, it meant 'thorny or spiny,' but over time it evolved into its current meaning of 'a group of extinct jawed fishes.'