D defs.my
Entry 5 senses · 2 variants Webster, 1913

Flatten

/(flăt"t'n)/ · Flat·ten · IPA /ˈflæ.tən/
01 v. t. To reduce to an even surface or one approaching evenness; to make flat; to level; to make plane.
imp. & p. p. Flattened; p. pr. & vb. n. Flattening
  1. 1.
    To reduce to an even surface or one approaching evenness; to make flat; to level; to make plane.
  2. 2.
    To throw down; to bring to the ground; to prostrate; hence, to depress; to deject; to dispirit.
  3. 3.
    To make vapid or insipid; to render stale.
  4. 4.
    To lower the pitch of; to cause to sound less sharp; to let fall from the pitch.(Mus.)
Phrases & compounds
To flatten a sail — to set it more nearly fore-and-aft of the vessel.
Flattening oven — in glass making, a heated chamber in which split glass cylinders are flattened for window glass.
02 v. i. To become or grow flat, even, depressed, dull, vapid, spiritless, or depressed below pitch.
  1. 1.
    To become or grow flat, even, depressed, dull, vapid, spiritless, or depressed below pitch.