62. Octopuses vs Octopi vs Octopodes: The Strange World of English Plurals

The plural of bird is birds, the plural of dog is dogs, but what is the plural of octopus? Is it octopuses, octopi, or octopodes? In this episode, we’ll discuss why no one seems to know the answer to this question, and look at the strange and confusing world of English plurals.


(If you can’t see the podcast player CLICK HERE to listen!)

Vocabulary List

Syllable (n) – a unit of speech which in English usually contains vowel, and can either be a whole word or one of the parts into which a word is separated when it is spoken 

There are two syllables in the word silver and three in appetite.

Perplexing (adj) – confusing, often because you do not know how to solve something

They find the company’s attitude perplexing and unreasonable 

Exception (n) – someone or something that is not included in a rule, group, or list or that does not behave in the expected way

There are exceptions to every rule

Isolation (v) – to process or fact of being separated, or kept separate, from other things

The prisoner was kept in isolation for three days

Baffling (adj) – confusing, not able to be understood or explained

This is a baffling mystery

Tentacle (n) – one of the long, thin parts like arms of some sea animals, used for feeling and holding things, catching food, or moving 

An octopus has eight tentacles

Specimen (n) – something shown or examined as an example; a typical example

He has a selection of rare insect specimens 


If you’ve been learning English for a while now, I’m sure you are already aware that every time English can confuse you, it will confuse you. For example there are many words in English known as contranyms (one word with two opposite meanings). If you clip something, are you cutting it or attaching it together? Confusingly, the answer could be either one! Moreover, the meaning of words can change depending on which syllable is stressed. For example, an ADDress is the place where someone lives, while to addRESS someone is to talk to them. A good tip for this confusing problem is that if the stress is on the second syllable, it is usually a verb! English is also full of puzzling spellings and silent letters. 

This episode of Thinking in English will focus on another perplexing part of English grammar: plurals. Plural means more than one, and when I talk about plurals I’m really talking about plural nouns – a word for more than one thing. Birds is the plural of bird, dogs is the plural of dog. Pluralisation, or making a noun plural, usually follows a very simple rule in English but there are some unpredictable exceptions

Most languages do not exist in isolation from other languages: over thousands of years they are influenced by vocabulary, grammar, and pronunciation from other parts of the world. English is an excellent example of such a language. Most of the time, when English borrows a noun from another language we usually make it plural using the basic English rules: add an ~s. However, in some situations a word will keep their ending from their original language, and this is what confuses people! Usually this happens with Latin words. A good example is that the plural of bacterium is not bacteriums, it is bacteria! Even more confusing is that sometimes these latin words can have two different plurals. Multiple stadium can be stadia or stadiums, and multiple phenomenon may be phenomena or phenomenons!  

English plurals are baffling. We all know that. But what about the title of this podcast? What are those words? Occasionally, native speakers will not agree on how to make a noun plural. This can result in two, or even three, options! Octopus is probably the most famous case. Depending on which dictionary you use, the plural of the eight tentacled sea creatures can be written in three different ways: octopi, octopuses, or octopodes! Why are there so many? Why can’t it be simple? The problem is actually not with the English language, but with English speakers who can’t decide in which one to use! People have been debating how to pluralize octopus for an incredibly long time.

To be completely honest, you will rarely, if ever, need to use the plural of octopus. When was the last time you found yourself needing to describe multiple specimens of the sea creature at one time? However, I think it is a really useful lesson to learn. As an English language learner, and especially if you are not a native speaker of a European language, you probably have never thought about the origin of the language you are learning or words you are using. You’ve almost certainly been confused by an English irregularity, but do you ever think about why? Often, the reason is because the word is borrowed from a foreign language.

Let’s get back to our friend the octopus. Why are there three plurals? Well, the oldest plural currently used is probably octopi which has been used since the early 19th century. This actually follows the Latin rule for plurals. Many people, especially in the past, believed that words of Latin origin should still have a Latin ending in English – so the ~i ending became popular. Although octopus is probably a Greek work originally, it arrived in English from Latin instead.

A different option for the plural follows the standard rules of English grammar. In other words, add an s to the end of the word. Most English words, and even words of foreign origin in English, are given English endings. If it’s in English, you are entitled to give the word an English ending. So, while octopuses might sound a little strange to some English speakers, there is absolutely nothing incorrect about it. It is perfectly acceptable. Moreover, if you use the word octopus as metaphor to describe a business or organisation, octopuses  is the most common form!

Octopodes is the rarest of the three options. As I mentioned before, the word octopus might actually be Greek. In the past, some people had the belief that a Greek word should have a Greek ending, just like a Latin word should have a Latin ending. Although it makes the word a little more difficult to understand, I guess this is why some people prefer this option. As your English improves, and you move on from Thinking in English and start listening to real native English podcasts, you’ll realise that some people love to use the most difficult version of the language possible. Octopodes fits nicely into this way of thinking about English – the more difficult the better!

Final Thought

This episode of Thinking in English has been a little different. I thought it would be interesting to introduce one of the most confusing aspects of English language; weird and irregular plurals! The case of octopus demonstrates this problem perfectly. There are three separate plural options, which have all been criticised in the past but are all used to a certain extent. If you want to choose the word that is most likely to be considered correct and understandable by your audience you should probably go for octopuses or octopi. Octopodes is the rarest and least used option! 

As I mentioned earlier, knowing the plural of octopus is probably not going to be too useful in your life. However, hopefully this episode might inspire you to think a little deeper about language. The reason the English language doesn’t always follow the standard English rules is because the English language is a mix of multiple different languages. Sometimes, depending on the origin of a word, the rules we use can change! It is not just English that does this. How about your language? What does your language do with borrowed words? How does the origin of a word affect its use in your language? 


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