2 Nouns

2.4 Endings in the plural

There are two different endings in the plural.

If the word has one syllable, it usually ends with -e in the indefinite form, and -ene in the definite form.

If the word has two or more syllables, the word ends with -er in the indefinite form, and -erne in the definite form.

Comparison:
In English the plural is usually formed with the addition of the ending -s to the singular.

boy
boys