'acrostichum' originates from Greek, specifically the word 'akrostichon', where 'akro-' meant 'top' and 'stichos' meant 'line'.

'akrostichon' transformed into the Latin word 'acrostichum', and eventually became the modern English word 'acrostichum'.

Initially, it referred to a type of poem where the first letters of each line spell out a word, but over time it evolved into its current meaning of a genus of ferns.