adjective • 1) containing, or made up, of, several languages. 2) versed in, or speaking, many languages.
noun • 1) one who speaks several languages. 2) a book containing several versions of the same text, or containing the same subject matter in several languages. 3) a program written in multiple programming languages (programming).
From Greek, πολύς (many) + γλῶττα (tongue, language)