In Arabic every word is in one of three categories: اسم  (ism), فعل  (fi‘l) and حرف  (ḥarf).

The category ism is often readily translated as “noun” but it includes more than just the Western definition of a noun as for example an adjective is also considered to be اسم . 

اسم  thus includes: nouns, names, pronouns, adjectives and adverbs