Nouns in Greek are declined (have ending changes) based on case, number (singular or plural), and gender (masculine, feminine, neuter).
The case of a noun indicates the function of the noun in the sentence. There are five different cases:
- The nominative case marks the subject of a phrase as well as the predicate nominative (i.e., the object of a linking verb (or copulative verb), such as to be). Examples: In the sentence "The dog bit the man", dog would be in the nominative case. Also, in the sentence "The man is a soldier", both "man" and "soldier" are in the nominative case.
- The genitive case denotes source or origin (this function is also called the ablative), or kind or possession. It is also often used for an object of a preposition. It is frequently translated as "of ...". Examples: In the phrase "The man's wife", or equivalently, "the wife of the man", man would be in the genitive case.
- The dative case denotes an indirect object (translated as "to ..." or "for ..."); means or agency, especially impersonal means (translated as "by ..."); or a location. It is also frequently used as an object of a preposition, and often, a preposition can take a noun in either the genitive or dative case with different meanings. Examples: In the sentence "I spoke to John", John would be in the dative case. Also, in the sentence "By grace, you have been saved", grace would be in the dative case.
- The accusative case denotes a direct object. Example: In the sentence, "I saw the cat", cat would be in the accusative case.
In Greek, nouns fall under three different patterns for case endings, called declensions. The first declension contains nouns whose stems end in α or η. They are mostly feminine nouns. The second declension contains nouns whose stems end in ο. They are mostly masculine or neuter. The third declension contains all other nouns (mostly, nouns whose stems end in a consonant). There are broad patterns in third declension endings, but much more special cases than for first and second declension nouns.