Ambiguity is the property of words, terms, and concepts (within a particular context) as being undefined, undefinable, or without an obvious definition and thus having an unclear meaning. A word, phrase, sentence, or other communication is called "ambiguous" if it can be interpreted in more than one way. Ambiguity is distinct from vagueness, which arises when the boundaries of meaning are indistinct. Ambiguity is in contrast with definition, and typically refers to an unclear choice between standard definitions, as given by a dictionary, or else understood as common knowledge.