Which plural ending would you use for a Latin noun ending in -on, such as phenomenon becoming phenomena?

Which plural ending would you use for a Latin noun ending in -on, such as phenomenon becoming phenomena?

• A. a
• B. ae
• C. i
• D. es

Answer: (A)

Neuter nouns that end in -on, especially those borrowed from Greek, form their plurals by changing -on to -a. This is why phenomenon becomes phenomena—the -on ending in the singular shifts to -a in the plural. A familiar parallel is datum turning into data, where the neuter ending changes in the plural. The other endings don’t fit this neuter- plural pattern: -ae is for feminine first-declension plurals, -i is a masculine plural ending in some second-declension nouns, and -es isn’t the standard Latin plural for -on nouns.

Neuter nouns that end in -on, especially those borrowed from Greek, form their plurals by changing -on to -a. This is why phenomenon becomes phenomena—the -on ending in the singular shifts to -a in the plural. A familiar parallel is datum turning into data, where the neuter ending changes in the plural. The other endings don’t fit this neuter- plural pattern: -ae is for feminine first-declension plurals, -i is a masculine plural ending in some second-declension nouns, and -es isn’t the standard Latin plural for -on nouns.