aside: me after reading the headline: Shouldn't that be Octopii? But no! "The plural form octopii is doubly incorrect. Firstly, octopus derives from Greek, not Latin; its etymologically-consistent plural form is octopodes. Secondly, even if octopus were a second-declension Latin noun, the plural form would be octopi; in the correct plurals radii and gladii, with which octopii is analogous, the first ‘i’s are part of…
While I'm all for a history lesson (and the double-I octopii is indeed simply incorrect) I take issue with anyone insisting that "octopi" is wrong: 1. Language is neither static nor a series of rules to be blindly followed. The way a word was pluralized 1400 years ago has limited relevance today. 2. As noted just about everywhere, "octopodes" looks insane in any modern English sentence because we don't pluralize any…
E.g. Look at all those octopus.
All the divers I know say it this way, easy to say, understand, doesn't make you sound like an asshole.