October 31st is celebrated in many countries as "Halloween". But why? What is the meaning of Halloween?
There are two parallel "meanings", both of which have some validity. Firstly there is the Christian festival of All Hallows in which those who have passed on, and especially Saints, are honoured. Secondly there is the Gaelic festival of Samhain (pronounced "sow-in"), which celebrates the end of summer and start of winter, and during which fairies and / or the spirits of the dead find it easier to cross over into this world and create mischief.
Most of the trappings of a modern Halloween celebration can be traced back to one or both of these festivals.
In the Gaelic festival, turnips were carved, often with faces meant to represent evil spirits, and candles placed inside so they could be used as lanterns. They were called "jack-o'-lanterns" after the name given to the weird lights that can sometimes be seen flickering over peat bogs. Immigrants to the US replaced the turnips with pumpkins as the inside of a pumpkin is much softer than a turnip, making it much easier to carve.
Jack-o'-lanterns were hung outside houses to light the way for the dead souls who wished to return one last time before they passed on to the next world and who chose to come on this one night when the veil between the two worlds was so much thinner. There is a similar festival honouring the dead to this day in Japan, the festival of Obon in mid August, where a trail of candles may be lit leading the returning spirits to their home.
The jack-o'-lanterns were also used to light the path of "soulers" (mainly children or poor people) who travelled from house to house asking for "soul cakes" in return for saying prayers for the dead. This tradition survives more or less intact today in the Portuguese "Pão-por-Deus", or "Bread in the name of God", where children up to around 10 years old knock on doors and ask for bread in the name of God, receiving not only bread but also sweets and even money. And of course it survives in the practice of "trick or treat", where children ask for sweets, and may play a trick on the householder if they don't get anything.
While "trick or treating", children usually dress up in various costumes. Also, many Halloween parties are fancy dress parties. The origin of this is the ancient belief that All Hallows Eve is the last chance the dead have of coming back to earth and taking vengeance on people who they believe have done them harm in some way. In order to avoid this ghostly vengeance, people would dress in disguise in the hope the ghosts would not recognize them.
Most of what you are likely to do at Halloween, if you celebrate it at all, will probably be simply for fun. There is nothing wrong with this - it is good to have fun. But perhaps you should also remember some of the deeper meanings of this festival. Remember those who have passed on, thinking of the good they have done in this world and vowing to do at least as much good yourself. Think of those worse off than yourself (as in the "soulers") and do what you can to help them. And perhaps also remember that the boundary between this world and other more ethereal worlds may not be as solid as you might believe and that, as the Bard himself once said, "there are more things in heaven and earth, Horatio, than are dreamt of in your philosophy".