the word is considered “adopted” into English from Greek origin. Even if it wasn’t, then Helga’s assertion that it is “octopodes” would be correct, but not “octopi”.

thank you... i typed a more lengthy response, but I see you got there first.

You’re in the correct “corner”, Helga (mostly). the use of “i” for plural applies to 2nd declension nouns borrowed from Latin. Octopus is a Greek-derived compound word, and it’s third declension, which is the one that has the less-predictable “irregular” endings in ancient Greek, so yes, “podes” is plural of “pous”…