'Halloween' definitions:

Definition of 'Halloween'

From: WordNet
noun
The evening before All Saints' Day; often devoted to pranks played by young people [syn: Halloween, Hallowe'en, Allhallows Eve]

Definition of 'Halloween'

From: GCIDE
  • Halloween \Hal`low*een"\ (h[a^]l`l[-o]*[=e]n"), n. The evening preceding Allhallows or All Saints' Day (November 1); also the entire day, October 31. It is often marked by parties or celebrations, and sometimes by pranks played by young people. [Scot.] --Burns.
  • Syn: Hallowe'en, Allhallows Eve. [1913 Webster + WordNet 1.5]