The case of specific designation, the naming case.
The Subject Nominative
This use denotes more specifically who or what produces the action or presents the state expressed by the finite verb. It is otherwise known as the “Nominative of Apposition.”
The Predicate Nominative
This is the use of the Nominative case in apposition after copulative verbs, i.e. εἰμι , γίνομαι, etc. The verb is often left out and must be supplied from the context. This use is sometimes called the “subject compliment.” It occurs where one would expect to find the Accusative case.
The Nominative Absolute
Here the Nominative case stands without connection to the rest of the sentence. It is used in titles to call attention emphatically to the person or thing spoken of. It is also called “the suspended,” “independence” or “hanging” Nominative. It refers to an idea. Most of the examples could fit into other categories.
The Nominative in Exclamations
This use of the Nominative is a sort of interjectional Nominative, which expresses feeling. It occurs without a verb to stress the distinctiveness of a thought.
The Parenthetical Nominative
This use is very similar to the Nominative Absolute. Its function is to explain or expand. Dana and Mantey refer to it under the “Independent Nominative.” Cf. the Nominative Absolute above.
The Nominative of Apposition
This use denotes more specifically who or what produces the action or presents the state expressed by the finite verb. It is otherwise known as the “Subject Nominative.”
The Nominative of Appellation
In this use, a noun or title retains the Nominative form irrespective of contextual relationships. Sometimes it is practically equivalent to quotation marks.
The Nominative Case Unaltered
The noun is not altered to the case of the noun with which it stands in apposition. […]