1) A non-banked, oval track flush to the ground on which the sport of roller derby can be played.
2) A type of roller derby governed in present day by the WFTDA (Women's Flat
Track Derby Association), with specific rules pertaining to bouts played on a rink with no banked edges or "rise".
3) A particularly D.I.Y.-type of Roller Derby, in that it requires only a flat, smooth floor, tape to measure out a track, and rollergirls to kick some booty.
"Though the spandex leagues of the 1970s fought their way to victory on a banked track, many of the 21st century leagues like New York's Gotham Girls Roller Derby have embraced the cost-effective, nomadic appeal of flat-track derby."