mezzanine
n. countablen. a small floor that is built between two main floors of a building. It is usually smaller and lower than the floors above and below it.
n. an intermediate floor between two main floors of a building, typically smaller in area and lower in height than the surrounding levels. Often used in architectural contexts to describe a gallery or a raised platform.
The library has a small mezzanine for quiet study.
The architect added a glass mezzanine to the office to provide a private meeting area above the main floor.
In many older theaters, the mezzanine serves as a secondary tier of seating, offering a more intimate perspective on the stage than the ground-level stalls.
PIE word *médʰyos The noun is borrowed from French mezzanine, and from its etymon Italian mezzanino, from mezzano (“(adjective) middle; (noun) go-between”) + -ino (diminutive suffix). Mezzano is derived from Latin mediānus (“central, middle”, adjective), from medius (“mid, middle”) (ultimately from Proto-Indo-European *médʰyos (“middle”)) + -ānus (suffix meaning ‘of or pertaining to’). The adjective and verb are derived from the noun.