The parts of speech that are often declined and therefore may have a nominative case are nouns, adjectives, pronouns and (less frequently) numerals and participles. The nominative case often indicates the subject of a verb but sometimes does not indicate any particular relationship with the other parts of a sentence. In some languages, the nominative case is unmarked, and it may then be said to be marked by a null morpheme. Moreover, in most languages with a nominative case, the nominative form is the lemma; that is, it is the reference form used to cite a word, to list it as a dictionary entry etc.