Arabic

Suffix

ـُون • ‎(-ūn) m

1. Oblique-case suffix—i.e. accusative-case (manṣūb) and genitive-case (majrūr)—used to pluralize masculine nouns and adjectives referring to people. In Classical Arabic, with full ʾiʿrāb, appears as ـِينَ ‎(-īna). Note that most masculine nouns and adjectives referring to people, especially shorter ones, are not pluralized in this fashion, but use a broken plural instead. Furthermore, non-human masculine nouns don't use this suffix, either forming a broken plural or using the "feminine" suffix ـَات ‎(-āt).
2. Oblique-case suffix used very occasionally to pluralize non-human nouns, including some that are feminine, such as سَنَة ‎(sana, “year”), accusative/genitive plural سِنِين ‎(sinīn).

See also

• ـُون ‎(-ūn) (for the nominative case)