Like many traditions throughout the year, the meaning of Halloween has morphed over the centuries and lost its original meaning. As most sources will tell you, the word Halloween comes from All Hallows Eve, or the eve of All Saints' Day, which is the first of November; hence the eve is October 31. The Oxford English Dictionary records the earliest use of All in 1556, and the latest in Shakespeare's Measure for Measure of 1616 (Allhallond-Eue). After that, the "All" seems to have dropped out of use.
All Hallows Eve(n) --> Hallows E'en --> Halloween
"Hallows" refers to a holy person, deriving from the old English word, halig for holy. We're familiar with the phrases "hallowed grounds," and "hallowed be thy name," in the Lord's Prayer, meaning venerated in those contexts. For an in-depth linguistic discussion of the history of Halloween, see this piece by Neal Whitman.
What might be less well-known is that although the word Halloween derives from a single source, the celebration itself draws on two historic celebrations: the ancient Gaelic (subset of Celtics) festival of Samhain, [pronounced, oddly enough, sow-win] (from sunset of October 31 to sunset November 1) and the Christian holiday of All Saints' Day. Here's a little bit about Samhain:
Samhain has pre-Christian roots and marks the end of the harvest season and the start of the darker half of the year. In Samhain, there was the belief that spirits, good and bad, could more easily enter the physical world. As part of the festival, people would gather to burn animals and crops in bonfires as sacrifices to the Celtic gods and deities. During the celebrations, people would dress up in costumes and dance around the bonfires. The point is, the festival was very much tied to the cycle of life and death. As was the habit of Christians, they annexed a "Christian" celebration, All Saints' Day, to a pagan one in the hopes of "converting" said pagans. (NB: paganism is not in itself evil, but it has become a derogatory word at the hands of monotheistic religions). The "trick-or-treat" tradition might have come from Irish and Scottish holidays in which people would dress up and visit homes to perform antics, sing a song, recite a poem, etc. in return for a treat.
Often discussed in this context is the Day of the Dead, or El Día de Los Muertos. This tradition dates back some three thousand years ago to the Aztec people. Celebrated in Mexico and elsewhere, it's sometimes incorrectly called, "Mexican Halloween." The "day" is actually Day of the Innocents on November 1, and Day of the Dead on November 2. Rather like the Celtic tradition of Samhain above, on the Day of the Dead, the border between the spirit world and the real world disappears. During this brief time, the souls of the dead come awake and return to the living world to celebrate. Hence, food and drink are left out at gravesides and on altars. Also prominent are decorative and elaborate skeletons and skull masks.
Dia de los Muertos festival in Mexico City (Shutterstock/IlanDerech)
Is there Halloween in Africa?
There is no original African celebration, event, or occasion on a selected day called "Halloween" as known in the US and other western countries that have adopted the tradition. Halloween's origins are not shared by African traditions, particularly as the history of Halloween is tied in part to the changing of the seasons from summer/autumn to winter. Certainly in West and Central Africa, there are only two seasons: wet and dry. Halloween has little relevance to most Africans, although there are signs that Halloween may be picking up in popularity in the Republic of South Africa.
I asked a Ghanaian friend who has never been out of Ghana about it; he had never heard of Halloween or All Saint's Day. (Arguably, Christmas shouldn't be relevant in Africa either as its origins are tied up with pagan traditions around the winter solstice. But Christmas, for lots of reasons not the least of which is Jesus is at the center of the tradition, is in a league all of its own all over the world.)
If Halloween parties are held somewhere in Africa, they would be almost certainly "borrowed" from the West and perhaps held by expatriates. In Rwanda in 2013, Halloween parties did not go down well with the Rwandan government, which banned such gatherings, stating that "hono[u]ring the spirits of the dead is inappropriate and against Rwandan culture." One reason why that could be the case in Rwanda and other African countries is that phenomena like spirits, the ancestors, magic, and juju are taken seriously and can even be part of daily life. Essentially, the African perspective--certainly West Africa--is don't joke around with that kind of stuff. Placing a mock graveyard with ghosts and ghouls in your front-yard as Halloween "fun" would be seen as seriously bizarre in Africa and probably offensive as well.
At the same time, there are many African ceremonies with a central theme of communicating with the ancestors, and some are performed with the wearing of elaborate masks, which represent the spirits of those ancestors e.g. FESTIMA in Burkina Faso, and Nigerian mask festivals. In other words, unlike modern Halloween, there is a deep meaning embedded in those traditions themselves.
The bottom line
Halloween has historical origins, but in modern times it's a commercialized celebration of dubious value in which children and adults dress up in costumes of all types--scary and not--often their alter egos or favorite superhero. It's also the warning that the interminable holiday season is about to begin, so start shopping.
And finally, what do pumpkins have to do with all this? All you need to know about this is there's an Irish legend with a guy called Jack whose ghost roams around restlessly. The carved pumpkin (originally carved turnips) is supposed to scare Jack away.
As time passes, perhaps the occasion will be called Holloween. One celebrant, an adult, thought the name originated from the fact that your stomach is hollow before you get all that candy from trick-or-treating.