Any word which may be modified by an adjunct.
A word used as the title of a section, particularly in a dictionary, encyclopedia, or thesaurus.
A sentence, phrase, or word, prefixed to an essay, discourse, chapter, canto, or the like, suggestive of its subject matter; a short, suggestive expression of a guiding principle; a maxim.
A sentence, phrase, or word, forming part of an heraldic achievement.