- to make flat.
- to knock down: The boxer flattened his opponent in the second round.
- to become flat.
- flatten in, Nautical. flat1(def 61).
- flatten out, Aeronautics. to fly into a horizontal position, as after a dive.
Origin of flatten
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- (sometimes foll by out) to make or become flat or flatter
- (tr) informal
- to knock down or injure; prostrate
- to crush or subduefailure will flatten his self-esteem
- (tr) music to lower the pitch of (a note) by one chromatic semitoneUsual US word: flat
- (intr foll by out) to manoeuvre an aircraft into horizontal flight, esp after a dive
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for flattener
Online Etymology Dictionary, © 2010 Douglas Harper