Nominative

[Sarah]

Giving a name; naming; designating; -- said of that case orform of a noun which stands as the subject of a finite verb.-- n.

[Dave Paprocki]

(being) a particular form of a noun in some languages that shows the noun is the subject of a verb

[Lanell]

Relating to or denoting a case of nouns, pronouns, and adjectives (as in Latin and other inflected languages) used for the subject of a verb.