Pronunciation: (hal"u-wēn', -ō-ēn', hol"-), [key]
the evening of October 31; the eve of All Saints' Day; Allhallows Eve: observed esp. by children in costumes who solicit treats, often by threatening minor pranks. Also,Hal"low•e'en'.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.