Webster's Revised Unabridged Dictionary · 1913

Lingua Franca

Lingua Franca (lin"gwȧ fran"kȧ) , noun

[Italian, prop., language of the Franks.]

1.
The commercial language of the Levant, -- a mixture of the languages of the people of the region and of foreign traders.
2.
Any hybrid or other language used over a wide area as a common or commercial tongue among peoples of different speech.