The current Halloween holiday comes from an old Celtic celebration called All Hallows Eve (translated to All Saints Day). During the festival they would bless and convert Pagans. We call it "Halloween" because "Hallow" means saints, and "-een" (originally e'en) means Evening. All Hallows Eve.
We dress up honoring the Celtics, who would wear masks to scare away evil spirits and prevent demons from identifying them as humans.
We even bob for apples simply to honor a fruit god that the Celtics honored. Trick-or-treating represents how the spirits would visit Celtics' homes disguised as people in hopes of claiming a new soul. The treat part is for the feast after the whole fiasco was over. More input from our contributors:
The word Halloween is derived from All Hallow's Eve. November 1 is All Hallows' Day, or All Saints' Day.
The festival has its roots in Pagan festivals surrounding the Autumn season as well.
Various traditions of singing, lighting candles, and rituals to ward off evil spirits or put the dead at peace evolved in several different cultures.
The commercialization of Halloween originated in North America.
It has something to do with All Hallows Day. They would dress up as scary things to scare away the evil monsters and spirits. Halloween is the evening before All Saints' Day. For me it's just a day for me to wear costumes and trick or treat for free candy.
Well to celebrate Halloween you need a couple of friends around the house, some kids... get ready with the spookiest trick o treats and amazing Halloween games... and yes not to forget the scary Halloween costume.
Another reason is because in the earlier times they had gatherings and would dress up in a costume. That was out of the country at that time, but when the immigrants came to this country they brought their culture. So that's how Halloween came about.
Halloween comes from a celebration long ago that the Celtics would celebrate, called All Hallows Eve, translated to All Saints Day, the festival where they'd bless & convert pagans. We call it 'Halloween' because 'Hallow' means saints, and '-een' (originally e'en) means Evening. All Hallows Eve, get it?
We dress up honoring the Celtics, who would wear masks to scare away evil spirits & not have the demons identify them as humans. Almost everything has to do with this whole celebration.
We even bob for apples simply to honor a fruit god that the Celtics honored. As for trick-or-treating, that dignifies how the spirits would visit Celtics homes disguised as people, in hopes of claiming a new soul. E.g. Trick, and treat is for the feast after the whole fiasco was over.
(See the Related link for more detailed information.)
This answer is closed to changes. This is done in rare cases when questions are being vandalized or answers have become debates. E-mail reopen @ answers.com (no spaces) if you would like it to be reopened.