Motto

Part of speech: noun (n.)

1. A sentence, phrase, or word, forming part of an heraldic achievment.

2. 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. It was the motto of a bishop eminent for his piety and good works, ... "Serve God, and be cheerful." Addison.