The plural of octopus has been a topic of debate for a long time, and there are three commonly used options: octopuses, octopi, and octopodes. The word "octopus" comes from the Greek word "októpus," which means "eight foot," and its etymological history reveals why there are different endings for the plural of octopus.

• Octopuses: This is the most commonly used plural form of octopus and is the preferred plural when speaking and writing in English. It emerged later in the nineteenth century and has the attached "-es" ending to follow the English formation of plurals.

• Octopi: This is the oldest plural form of octopus, coming from the belief that Latin origins should have Latin endings. However, octopus is not a Latin word, and using "octopi" is considered incorrect by many experts.

• Octopodes: This plural form follows the Greek formation for plurals and is the least-used ending. It stems from the belief that because octopus is originally Greek, it should have a Greek ending.

In conclusion, the most commonly accepted plural usage for octopus is "octopuses".