An octopus is a marine cephalopod mollusk that has a soft body and eight arms. What word should we use if we are referring to more than one of these invertebrate animals?
Unlike many words in the English language, the word octopus has more than one spelling for the plural: octopi and octopuses.
Examples
While we were deep-sea diving, we saw several octopi.
While we were deep-sea diving, we saw several octopuses.
Dating from the early 19th century, octopi is the older of the two options. Octopuses dates from later in the 1800s.
Merriam-Webster also mentions a third plural, octopodes. This uncommon plural has a Greek ending and is not a preferred option for daily formal writing.
Both octopi and octopuses are correct, acceptable words to use in American English.
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