Of or relating to the theory that planet Earth is flat.

plural of flat dog

The belief in, or advocacy for, the theory that the planet Earth is flat.

A small patch of a vehicle tyre that has been flattened by abrasion with the road surface, so that the tyre is no longer smoothly circular at that point; usually caused by the wheel locking under heavy braking.

To cause a flat spot on (a vehicle tyre), usually by locking the wheels under heaving braking.

(UK, obsolete, slang) A bedbug.

(theater) Broadway flat

Synonym of diminished fifth

plural of flat passer

(gambling, slang) A crooked die that is shaved down on certain sides to produce the desired rolls more frequently.