To make something flat or flatter.
As there was a lot of damage, we chose the heavy roller to flatten the pitch.
To press one's body tightly against a surface, such as a wall or floor, especially in order to avoid being seen or harmed.
To knock down or lay low.
The prize fighter quickly flattened his challenger.
To become flat or flatter; to plateau.
Prices have flattened out.
To be knocked down or laid low.
To lower by a semitone.
To make vapid or insipid; to render stale.
To reduce (a data structure) to one that has fewer dimensions, e.g. a 2×2 array into a list of four elements.
To combine (separate layers) into a single image.
The act, or the result of making something flat of flatter
A flattened part of something
The Earth is a sphere that has flattenings at the poles.