- the eve of All Saints' Day celebrated on Oct 31 by masquerading; Allhallows Eve
WordReference Random House Learner's Dictionary of American English © 2015
- Religionthe evening of Oct. 31;
the eve of All Saints' Day, observed esp. by children, who dress in costume and play trick or treat.
- Religionthe 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.
- (All)hallow(s) + e(v)en2 1550–60