Why is the plural of apparatus apparatuses and not apparati?

You're right to be curious! The plural of "apparatus" is actually both "apparatuses" and "apparatus." It's a bit of a linguistic quirk.

Here's the breakdown:

* Apparatuses: This is the more traditional plural, following the standard English pattern of adding "-es" to nouns ending in "-us."

* Apparati: This is the more Latinate plural form, directly reflecting the plural of "apparatus" in Latin.

Both forms are considered correct, but "apparatuses" is generally more common in modern English.

It's similar to the situation with "octopus" – "octopuses" is the more common plural, but "octopi" is also accepted.

Ultimately, the choice of plural depends on personal preference and the context of your writing.