What is "troffer"

n. A rectangular, trough-shaped light fixture, typically for mounting in or on a ceiling to light the area below, and usually containing two or three fluorescent bulbs.(cite web url=http://dictionary.reference.com/browse/troffer?s=t title=troffer work=dictionary.com accessdate=November 10, 2012)

A troffer is a rectangular light fixture that fits into a modular dropped ceiling grid (i.e. 2' by 2' or 2' by 4'). Troffer fixtures have typically been designed to accommodate standard fluorescent lamps ( T12, T8, or T5), but are now often designed with integral LED sources. Troffers are typically recessed sitting above the ceiling grid, but are also available in surface mount 'boxes'.