Nouns are an essential part of Greek grammar and are categorized based on gender, number, and case. Gender refers to the distinction between masculine, feminine, and neuter nouns. It is important to note that there is no set rule to determine the gender of a noun and it must be memorized. Number refers to whether a noun is singular or plural. Singular nouns typically end in -ς, -ςς or -ος, while plural nouns end in -ι or -οι. Lastly, case refers to the function of a noun within a sentence. Greek has five cases: nominative, genitive, accusative, dative, and vocative.

The nominative case is used for subjects and predicate nouns, while the genitive case shows possession or origin. The accusative case is used for direct objects, the dative case indicates the indirect object or recipient, and the vocative case is used for direct address.

Understanding and utilizing nouns correctly is crucial for Greek language learners. Proficiency in noun theory enables students to construct meaningful and accurate sentences, as well as engage in more advanced reading and writing activities.