Earlier quoted context omitted.
> Octopi is not the correct plural. Octopi is not the most common plural, true. > Octopus is of greek origin, not latin. Octopus entered English from scientific Latin. In which the Greek plural was not used. (Lots of words in English fron languages other than their language of origin and have irregular English forms from their immediate source rather than their remote origin.) “Octopi” appears to be the earliest Engl…
This is fascinating and instead of replying I've been reading about this and looking up words like cacti. For what it's worth, both plural forms for Octopus are in my phone's autocomplete dictionary.
Snicker ... The new Webster or Oxfords ...