Wikipedia has a section in this, which I found interesting: > The standard pluralised form of octopus in English is octopuses; the Ancient Greek plural ὀκτώποδ

Wikipedia has a section in this, which I found interesting: > The standard pluralised form of octopus in English is octopuses; the Ancient Greek plural ὀκτώποδες, octopodes, has also been used historically. The alternative plural octopi is usually considered etymologically incorrect because it wrongly assumes that octopus is a Latin second-declension -us noun or adjective when, in either Greek or Latin, it is a third-declension noun. https://en.wikipedia.org/wiki/Octopus#Etymology_and_pluralisation https://en.wikipedia.org/wiki/Octopus#Etymology_and_pluralis...