This chapter explains the Noun attributes such as number, gender, case, definiteness. The morphological nature of the structure of Arabic words is such that, apart from its core meaning, a noun has four attributes: number, gender, case, and definiteness. Gender is either masculine or feminine. There is no neutral category. Case is nominative, accusative, or genitive. Definiteness is definite or indefinite. The morphological nature of the structure of Arabic nouns is such that the attributes are intertwined in a single word. Therefore, we cannot easily examine them in isolation. The typical anatomy of a noun can be represented morphologically by columns showing a noun and the relative position of each of its attributes. Dual nouns are marked by the compound dual suffixes aani or ayni. Masculine sound plurals and feminine sound plurals behave predictably when transformed from their singular to plural forms.