Formation of Plural Nouns

To make a noun plural, you usually add an -s. But there are some

Sing. Plural

exceptions:

If a noun already ends in an -s, add nothing. bus le bus les bus

If a noun ends in -eu or -eau, add an x. boat le

bateau les bateaux

If a masculine noun ends in -al or -ail, change it to -aux. horse le cheval les

chevaux

Some nouns ending in -ou add an -x instead of -s. knee le genou les genoux

There are, of course, some weird exceptions: un œil (eye) - des yeux (eyes); le ciel (sky) - les cieux

(skies); and un jeune homme (a young man) - des jeunes gens (young men).