furr down

a ceiling or part of a ceiling that is lower than the primary ceiling structure. A furr down is often constructed to enclose ducts or pipe that cannot be installed in the ceiling framing spaces and must be installed below the standard ceiling level. The rectangular finished structure above kitchen cabinets is often referred to as a furr down. Also called "Furred Ceiling", "Furred Down Ceiling" and "Drop Ceiling". Alternate spellings: "furdown", firdown" or "furrdown".