Recently I’ve noticed octopi being referred to as octopuses. Now when I was young I was taught it was octopi. Same with fungi & cacti. I’ve always been careful to get the plural right.
So I looked 'em all up & sure enough, -es is just as correct as -i.
When did that happen, or has it always been that way?
I think that since the late 1980s, it’s been more politically correct to refer to them in the plural as “Cephalopod Americans”.
Just because they’re both in the dictionary doesn’t necessarily mean they’re both equally correct. Most often, the first given form is the best one to use. I notice the American Heritage gives octopuses first and octopi second, while the OED gives octopodes first and octopuses second. I would call octopi wrong, because octopus is not a Latin word, but Greek. The correct Greek plural is octopodes, but that doesn’t necessarily mean octopodes is the correct English plural. After all, we don’t use sögur as the plural of saga, even though sögur is the correct Icelandic plural of saga.
The Cephalopod Page FAQ (Why octopuses instead of ‘octopi’ ‘octopodes’ or ‘dem theayr things’?) agrees with bibliophage that on etymological grounds the preferred plural in English ought to be “octopuses”, followed by “octopodes” if one wishes to be pedantic, with “octopi” rejected. And what could be more authoritative on such a topic than bibliophage and the Cephalopod Page FAQ?
Ok, so why even have two plurals? Which reminds me…
Cecil is always talking about how english spelling wasn’t standardized until the 1800’s or some such. Which of course explains why the UKs are always spelling things wrong. 
You see night being spelled nite all the time these days. Isn’t it about time English was re-standardized? Who has the authority to do it? Is it even being planned? If so, what’s the hold up?
Octopoi is simply wrong. If you want to speak classical Latin, then octopodes is the correct plural. But if you speak English, my opinion is that octopuses is correct.
Why is it that when speaking English we use Greek and Latin plurals, but never (well hardly ever), the plurals from other languages. Are more than one maven mavens or mavenim (or whatever is correct)? At least one style book I have read (I would love to know the reference) announces that English plurals are never wrong. And I have tried to stick to that.
My real pet peeve is that every classical plural eventually seems to get to be used as a singular. Data and media come to mind, but I have heard phenomena so used.
This one caught me by surprise, too. I was using octopi to someone who knw his ephalopods, and he corrected me by yanking out his Oxford English Dictionary and showing me – octopodes or octopuses. In my book, either is correct. In fact, I use both in my book, where I related this story.
The thing that surpried me is that this guy had apparently never heard anyone use * octopi* before, whereas I used it precisely because I’d heard it so ofen.
It sure is. Regular poi is quite disgusting enough.
Hari Seldon, add “criteria” to your list of plurals used as the singular form. I’ve corrected it at least 5 times this week in student papers. I seem to remember a Latin teacher talking about back formation and neutral plurals being confused with feminine singulars, but that particular datum has gone the way of much of my college education.
In fact, in several dictionaries I have certainly seen “octopi” being given as the plural for “octopus.” In fact, do a search at http://www.dictionary.com, and you will find the American Heritage Dictionary giving “octopuses” and “octopi” as plurals. If you’re gonna be pedantic and use Latin plurals, at least use the correct ones. This doesn’t seem to be an American phenomenon, either, as several Cantebrigian friends of mine also recall being taught “octopi” as the plural. It just must be a natural reflex to pluralize any Latin word ending in the syllable sounding “us” to “i.” Perhaps we’ve heard people pluralize “penis” as “penii,” instead of the classically proper “penes.”
That said, up with Anglo-Saxon! Down with Latinate plurals!
Hijack, but the history of “aluminum” and “aluminium” is an interesting lesson in how English is made. (“Aluminum” is correct, incidentally; the “ium” ending was a bit of Oxbridge pretension in the 1820s.)
As noted, the OED doesn’t agree with this, and gives the plural as octopodes. Apparently “octopus” isn’t first or second declension, but an irreguylar third, and has an irregular plural, as does “opus” (plural “opera”). Ordinarily I’m a little skeptical of the OED, but in this case the plural includes the form “–podes”, from the word for “foot” (pes, pluyral podes), which makes me tend to agree with it. The form “–pi” doesn’t make etymological sense.
[slight hijack]
When I learned English in school, at age 9, 1970, we started with basic words: One dog, two dogs, but when we came to fish the system broke down… “Fish and sheep don’t get plurals. They’re always one sheep, two sheep.”
But lately, I’ve been hearing fishes quite often on TV, and looked it up at Webster’s online. Shure enough - fishes is correct. Was my teacher wrong? Have I been saying it wrongly for all these years?
[/slight hijack]
“Fishes” is the plural for types of fish. “I am a marine biologist, and I study the sponges, the cetaceans, and the fishes.”
Dictionaries are descriptive, not prescriptive. They capture the language as it is spoken and do not make judgements about what is “right” or not. “Nauseous” used to mean “nauseating,” i.e. causing nausea. Nowadays most people mean “nauseated” when they use the word. This sort of grammatical slippage is common; in a hundred years, “penultimate” will be defined as synonymous with “ultimate,” even though, technically, it’s wrong, because so many people these days are using it that way.
As a student of Linguistics, I couldn’t agree more. When language is looked at as a science, descriptive linguistics is the only way to go. As for English, it basically boils down to “If people say it, then it’s English.” This is one of the most influential processes by which languages change and evolve. People use it in casual speech and it becomes the norm.
Granted, I would never use something unconventional in an official, academic or business setting, but I would have no problem saying “octopi” in conversation if I felt like it. For me at least, mutual understanding is key. YMMV
Yes, yes, yes. Of course, the ol’ descriptive thing. I am very much aware of this. However, the American Heritage Dictionary is especially good at giving Usage Notes for words that are etymologically suspect or which cause controversy among prescriptive grammarians. I would think “octopi” would be in this category. Especially since I find “octopi” a particularly pedantic plural, one would assume that, at any rate, the dictionary would at least list “octopodes” as another possibility (the technically correct one.) However, it doesn’t at all.
Just to be clear, octopus is a Greek word, not a native Latin word.
It’s made up of okto- (8) and pous, Greek for foot, which is a d-stem noun in the Greek 3rd declension, with stem pod- and nominative plural podes.
There’s a convention in English to use a Latinised version of the spelling of Greek words, so oktopous -> octopus.
If you wanted to make a native Latin octopus, it would be an octipede (ped-, a foot)
Note that both (foot, pod-, ped) and (eight, okto, octo/i) are all cognates of each other and 100% inherited ancestral Indo-European words (excited? who wouldn’t be!)
Heh, octipede makes me think of a little crippled centipede 
Heh, heh. pulykamell said penis. Heh.
Actually, I kinda like “penii,” but for the life of me I can’t think how to work that into everyday conversation.
The basic problem is as follows:
In Latin, masculine nouns that end in “us” are made plural by replacing the “us” with “i.”
Latin words that enter the English language tend to follow the old Latin rules. “Alumnus” is a Latin word- hence, in both English AND Latin, the plural of “alumnus” is “alumni.”
When people see a long word that ends in “us,” they tend to assume it comes from Latin. And they tend to follow the Latin rules, and pluralize it by replacing the final “us” with “i.”
However, not all long words that end in “us” come from Latin! “Hippopotamus,” for example, is a GREEK word, not a Latin word. So, the proper plural should NOT be “hippopotami,” but “hippopotamuses.” Similarly, “octopus” is not a Latin word… not a pure one, anyway. So, the plural should be octopuses, not octopi.
But back to the real world- no matter what lexicographers try to tell us, in the end, it’s ordinary people and common usage that determine whether words live or die, how they’re spelled, how they’re pronounced, and how their plurals are formed.
In other words, if enough people use the “wrong” words long enough, they become the “right” words. So, almost every dictionary now accepts “hippopotami” and “octopi” as correct- right along with “hippopotamuses” amd “octopuses.”