The other day, I overheard my kids having a passionate debate about the plural of “octopus.” My son insisted that the correct word was “octopi,” while my daughter argued that it was actually “octopuses.”

This debate brought to mind an article that TWFH’s Office Manager, Kathy Rinchuiso, recently shared with us about the general rules of pluralization in the English language. The article starts by explaining that plurals of most English words are formed by adding an “s” to the singular. For example:

• Car becomes cars
• Dog becomes dogs
• Flower becomes flowers

However, if the noun ends in -s, -x, -z, -ch, or -sh, an extra syllable must be added in order to pronounce the plural. In these cases,  -es is added, as follows:

• Crash becomes crashes
• Lunch becomes lunches
• Blitz becomes blitzes

And, if a noun ends with a -y, it must be changed to an -i, with -es added to the end to make it plural. For example:

• Party becomes parties
• Fairy becomes fairies
• Baby becomes babies

Of course, this is English, so it can’t always be that simple. And “rules” don’t always apply. Let’s get back to the debate my kids were having, as a perfect example of this.

Following the general rules of English, we would conclude that the plural of octopus is octopuses. However, depending on what dictionary you are consulting, the “correct” pluralization could be octopuses, octopi, or even octopodes.

Confusing, right?

This is because most English words have roots in other languages, primarily Latin and Greek. And some people believe that words with Latin roots should have Latin endings, while words with Greek roots should have Greek endings. If we follow this ideal, these Latin-rooted words would be pluralized the following ways:

• Alga becomes algae
• Vortex becomes vortices
• Analysis becomes analyses

Similarly, these Greek words would follow the Greek rules for pluralization:

• Stigma becomes stigmata
• Criterion becomes criteria
• Ganglion becomes ganglia

As you can see, some of these words are actually what are commonly used as plurals in English. Yet, other words that are based in Latin and Greek follow the English rules for pluralization.

But where does octopus end up in all of this?

Since “octopus” ends in a ‘-us’, most people assume it comes from Latin and thus spell the plural “octopi.” However, “octopus” actually comes from Greek, so the correct plural would be “octopodes.”

But we are speaking English here, so shouldn’t we use “octopuses?”

I think the real answer is that there is no exact answer. And the only thing we can really count on is that English will never fail to keep us on our toes!