MEZZANINE (It. mezzano; Fr. entresol; Ger. Zwischengeschoss) , in architecture, a storey of small height introduced between two lofty storeys, or sometimes employed to allow of the introduction of two storeys equal together in height to lofty rooms on the same floor.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)