METONYMY n.
A trope in which one word is put for another that suggests it; as, we say, a man keeps a good table instead of good provisions; we read Virgil, that is, his poems; a man has a warm heart, that is, warm affections.
MOTTO n.
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. It was the motto of a bishop eminent for his piety and good works, ... "Serve God, and be cheerful." Addison.