Halloween

or Hal·low·e'en

[ hal-uh-ween, -oh-een, hol- ]
/ ˌhæl əˈwin, -oʊˈin, ˌhɒl- /

noun

the evening of October 31; the eve of All Saints' Day; Allhallows Eve: observed especially by children in costumes who solicit treats, often by threatening minor pranks.

Origin of Halloween

First recorded in 1550–60; (All)hallow(s) + e(v)en2
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for hallowe'en

Halloween

Hallowe'en

/ (ˌhæləʊˈiːn) /

noun

the eve of All Saints' Day celebrated on Oct 31 by masquerading; Allhallows Eve

Word Origin for Halloween

C18: see Allhallows, even ²
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