The Collaborative International Dictionary of English v.0.48:

Polyglot \Pol"y*glot\, a. [Gr. poly`glwttos many-tongued; poly`s
   many + glw^tta, glw^ssa, tongue, language: cf. F.
   polyglotte.]
   1. Containing, or made up, of, several languages; as, a
      polyglot lexicon, Bible.
      [1913 Webster]

   2. Versed in, or speaking, many languages.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Polyglot \Pol"y*glot\, n.
   1. One who speaks several languages. [R.] "A polyglot, or
      good linguist." --Howell.
      [1913 Webster]

   2. A book containing several versions of the same text, or
      containing the same subject matter in several languages;
      esp., the Scriptures in several languages.
      [1913 Webster]

            Enriched by the publication of polyglots. --Abp.
                                                  Newcome.
      [1913 Webster]

WordNet (r) 3.0 (2006):

polyglot
    adj 1: having a command of or composed in many languages; "a
           polyglot traveler"; "a polyglot Bible contains versions
           in different languages"
    n 1: a person who speaks more than one language [syn:
         linguist, polyglot]