FLATTEN
flatten, drop
(verb) lower the pitch of (musical notes)
flatten, flatten out
(verb) become flat or flatter; “The landscape flattened”
flatten
(verb) make flat or flatter; “flatten a road”; “flatten your stomach with these exercises”
Source: WordNet® 3.1
Etymology
Verb
flatten (third-person singular simple present flattens, present participle flattening, simple past and past participle flattened)
(transitive) To make something flat or flatter.
(reflexive) To press one's body tightly against a surface, such as a wall or floor, especially in order to avoid being seen or harmed.
(transitive) To knock down or lay low.
(intransitive) To become flat or flatter; to plateau.
(intransitive) To be knocked down or laid low.
(music) To lower by a semitone.
To make vapid or insipid; to render stale.
(programming, transitive) To reduce (a data structure) to one that has fewer dimensions, e.g. a 2Ă—2 array into a list of four elements.
(computer graphics, transitive) To combine (separate layers) into a single image.
Source: Wiktionary
Flat"ten, v. t. [imp. & p. p. Flattened; p. pr. & vb. n. Flattening.]
Etym: [From Flat, a.]
1. To reduce to an even surface or one approaching evenness; to make
flat; to level; to make plane.
2. To throw down; to bring to the ground; to prostrate; hence, to
depress; to deject; to dispirit.
3. To make vapid or insipid; to render stale.
4. (Mus.)
Definition: To lower the pitch of; to cause to sound less sharp; to let
fall from the pitch. To flatten a sail (Naut.), 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.
Flat"ten, v. i.
Definition: To become or grow flat, even, depressed dull, vapid,
spiritless, or depressed below pitch.
Source: Webster’s Unabridged Dictionary 1913 Edition