polyglot

A publication in several languages; specifically, a book (especially a bible) containing several versions of the same subject matter or text in several languages.

[T]hose coming to the warehouses' doors fired them, and burned all the books and the pillars of the church, […] A great want thereof there will be of books, specially Latin books and foreign books; and, among others, the Polyglottes and new Bible, which he believes will be presently worth £40 a-piece.

But ſince that period the biblical apparatus has been much enriched by the publication of polyglots; […]

One who has mastered (especially when able to speak) several languages.

Laſtly, a polyg[l]ot or good linguiſt may alſo be term'd a uſefull learned man, ſpecially if vers'd in School-languages.

A mixture of languages or nomenclatures.

A file that can be interpreted validly as multiple formats.

If you are interested in polyglot file formats, take a look at the polyglot web page in the Corkami wiki. There are various example polyglots, including a PDF file that is also a valid HTML file with JavaScript, as well as a valid Windows PE executable.

A program written to be valid in multiple programming languages.

Of a person: speaking, or versed in, many languages; multilingual.

'[T]is thought the two and twenty Languages which Mythrydates the great Polyglot King of Pontus did ſpeak, wer all within the circumference of Anatolia in regard his dominions extended but a little further: […]

For this flyaway son of a Phœnician did not seem to wait for the decision of the polyglot Judges of the Emigration Board.

Containing, or made up of, several languages; specifically, of a book (especially a bible): having text translated into several languages.

a polyglot bible    a polyglot lexicon

Comprising various (native) linguistic groups; multilingual.

A polyglot region without a clearly dominant culture may develop an artificial lingua franca, such as Pidgin English in the South Sea.