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]

Moby Thesaurus II by Grady Ward, 1.0:

28 Moby Thesaurus words for "polyglot":
   atlas, bilingual, calendar, casebook, catalog, catalogue raisonne,
   city directory, classified catalog, concordance, cyclopedia,
   diatesseron, dictionary catalog, diglot, directory, encyclopedia,
   gazetteer, harmony, index, linguist, multilingual, phone book,
   record book, reference book, source book, studbook, telephone book,
   telephone directory, work of reference