There are 2 types of Arabic nouns, with sub-types of each type. The first type is proper nouns (اسم عَلَم) which refer to a particular person, place, etc. Examples of these are (محمد), (يوسُف), (مَكّة), (فلسطين), etc. These nouns are definite because they are names of particular people or places; therefore, they cannot be made definite by having (ال) at the beginning or a possessive noun at the end.

The second type is generic nouns (اسم جنس) which is a noun that refers to a thing with no specific reference, e.g. (رجل) ‘man’, (شجرة) ‘tree’, (حصان) ‘horse’, etc. These nouns do not refer to a particular man, tree or horse, but to any noun that belongs to the relevant class.