Language Matters | Octopus word origin, the correct plural form, and the Chinese idiom that gave birth to the name of Hong Kong’s famous travel card
- While the origins of the word ‘octopus’ are fairly straightforward, what isn’t so clear is the correct form of the plural – is it octopi, octopuses or octopodes?
- Far-reaching influence or power, usually harmful or destructive, has been a figurative meaning associated with octopus, though such connotations are changing

October is Octopus month, with World Octopus Day on October 8, of course.
The octo- in the name of the month and the cephalopod mollusc means “eight”, from the Greek ὀκτώ oktō. -Pus comes from the Greek πους pous, from the Proto-Indo-European root *ped, meaning “foot”.
The word “octopus” was, in fact, coined in scientific Latin from ancient Greek, standardised in 16th century Linnaean taxonomy and later adopted into English. In ancient Greek, the creature was known as polypous “many-footed”, which was later borrowed into Latin as polypus (with forms in other languages).
What is usually less clear is how to speak of several of these creatures. A poll of my three-person household demonstrated the split perfectly – octopuses, octopi and octopodes – and illustrates how the English language determines its plural forms.
Appearing earliest in English, in 1816, is octopi, a widely used form.