Greek Thought for the Day (David L. Mathewson and Elodie Ballantine Emig)

Defining the Greek nominative case has posed a challenge for grammars. Sometimes it is described in terms of one of its primary functions, to indicate the subject of a sentence (Dana and Mantey 68–69). Though this is one of its common uses, the description is too narrow and does not account for all of the nominatives. As frequently recognized, the Greeks themselves designated it as the “naming case” (Robertson 456). The nominative is the case that designates, or specifies, a nominal idea. It simply names or designates an entity rather than specifying a relationship (as with the genitive or dative).3 The various syntactic functions explained below may be understood in this light. Furthermore, in relation to the other cases, the nominative is the unmarked case and carries the least semantic weight (but perhaps sometimes more marked than the accusative; see below), although at times it can have important functions in a discourse.

Mathewson, David L.; Emig, Elodie Ballantine. Intermediate Greek Grammar: Syntax for Students of the New Testament (Kindle Locations 318-325). Baker Publishing Group. Kindle Edition.