Dictionary.com
Thesaurus.com

didn't

American  
[did-nt] / ˈdɪd nt /
  1. contraction of did not.


didn't British  
/ ˈdɪdənt /

contraction

  1. did not

"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

Usage

See contraction.