Nominative case

In grammar, the nominative case (abbreviated NOM), subjective case, straight case or upright case is one of the grammatical cases of a noun or other part of speech, which generally marks the subject of a verb or the predicate noun or predicate adjective, as opposed to its object or other verb arguments. Generally, the noun "that is doing something" is in the nominative, and the nominative is often the form listed in dictionaries.