Flat describes something with a level, even surface, without curves, bumps, or slopes. A tabletop is flat. A basketball court is flat. When you smooth out wrinkled paper, you're making it flat.

The word applies to many situations. A flat tire has lost its air and lies deflated against the ground instead of staying round and firm. When a singer performs off key and misses the right notes, musicians say they're singing flat. A flat refusal means a direct “no” with no room for discussion or compromise.

In Britain and many other countries, flat also means an apartment: a place to live that's typically all on one floor (or level) of a building.

Flat can describe something dull or lifeless. A joke that nobody laughs at falls flat. When a story lacks excitement, you might call it flat. Soda left open overnight loses its fizz and tastes flat.

The word sometimes means absolute or exact, especially with time and speed. If you run a mile in six minutes flat, you've finished in exactly six minutes, not a second more. When someone says they finished their homework in ten minutes flat, they're emphasizing how quickly they completed it.