Samhain is the turning point of the year; it is the Celtic New Year’s Eve, sometimes referred to as the Feast of the Dead, Feast of Apples, or Ancestor Night. When the new religion, Christianity, adopted this festival – as was done with so many of the old pagan celebration – they aligned it with their own festival known as All Saints, All Souls, or All Hallows. The eve of it, which is when pagans and Witches would actually do their celebrating, was All Hallow’s Evening. This became shortened to Hallow’s Eve or Hallowe’en.
Witches call it Ancestor Night because this is the time – between the end of the old year and the start of the new – when it is felt that the veil between this world and the next is very thin and therefore it’s much easier to contact the spirits of your dead loved ones. Indeed, this was how the jack-o’-lantern originated. When traveling to the Sabbat site, Witches would believe that the spirits of their dead traveled with them. To light their way, the Witches would carry lanterns, often made out of hollowed-out turnips or pumpkins with a candle inside. It was then only a short step to carving a face on such a lantern so that it could better represent the departed spirit traveling along.
The focus of Samhain is honoring the dead, along with winter preparations and divination. It is a time for getting rid of the things you don’t want to have to take with you through the winter. In the old days, even the herds and flocks would be thinned, so there would be meat on hand through the winter and so there wouldn’t be unnecessarily large numbers of animals to have to feed in the hard months to come.
It is traditional on Samhain night to leave a plate of food outside the home for the souls of the dead. A candle placed in the window guides them to the lands of eternal summer, and burying apples in the hard-packed earth "feeds" the passed ones on their journey.
– Raymond Buckland and Scott Cunningham