flatten something out Definition

flatten
verb flattened, flattening

tr & intr
1. To make or become flat or flatter.

Thesaurus: crush, squash, compress, raze, level, trample, floor, demolish, knock down, prostrate, fell, smooth.
2a. colloq
To knock someone to the ground in a fight;
2b. colloq
To overcome, crush or subdue someone utterly.
3. music.
To lower the pitch of (a note) by one semitone.

Phrasal Verb: flatten something out

To make something flat or flatter.To bring (an aeroplane) into a horizontal flying position.