What Is Halloween and Why Do We Celebrate It?

You think you know what Halloween is all about, but you might not—not really. After all, it wasn't always about carving pumpkins and collecting candy.

Trick-or-treating, Halloween parties, costumes, carving pumpkins, and haunted houses—if you grew up celebrating Halloween this is likely how you envision October 31 always was, but the holiday has changed a lot over the years. In fact, if you were able to time travel back and watch the Halloween origin you probably wouldn’t even recognize it. So before you start a list of Halloween costume ideas, plan your Halloween party games, set up your outdoor Halloween décor, or brush up on your Halloween trivia; read on for the true Halloween origin story.

What is Halloween?

As it exists today in the United States, Halloween is a holiday when we can all indulge in the darker, creepier side of life and eat loads of candy. It’s a lot of fun, a little spooky, and anything but serious. Historically, however, the holiday was religious in nature and extremely significant to the culture of the people who celebrated it.

What does the word “Halloween” mean?

“The word, ‘Halloween,’ is a contraction of the Scottish term ‘All Hallows’ Eve,’ which simply described the night before All Saints Day,” says Brian Sterling-Vete, PhD, historian, Halloween expert, and author of Paranormal Investigation: The Black Book of Scientific Ghost Hunting and How to Investigate Paranormal Phenomena. The first records we have of it being used this way date back to around 1555 AD.

All Saints Day started with early Christianity. In the eighth century, Pope Gregory III moved the feast of All Martyrs’ Day from May 13 to November 1 and turned it into All Saints’ Day. Then, in 1000 A.D., the Catholic Church added All Souls’ Day (which focuses on praying for the dead) on November 2. The evening before was subsequently called All Hallows’ Eve…and then Halloween.

At that time, it was a religious day bearing very little resemblance to the modern holiday. The word Halloween and the holiday as we’ve come to understand it today, didn’t become popular until around 1745, says Sterling-Vete.

When is Halloween?

In America, Halloween is always celebrated on October 31. Countries that celebrate Halloween as we do, like Canada, share the same day. However, not everyone is as Halloween-obsessed as Americans.

In England, Halloween is generally not celebrated at all. That was a result of the Protestant Reformation. Instead, the United Kingdom celebrates a completely unrelated holiday around this time (on November 5th, to be precise): Guy Fawkes Day, which revolves around the execution of an infamous traitor, features bonfires, burning effigies, and fireworks.

In Mexico, people celebrate Día de los Muertos, the Day of the Dead. While it takes place from October 31 to November 2, it is very different in tone from Halloween. Yes, people do dress up as colorful skeletons and celebrate in the streets, but the point is to honor the dead and welcome their spirits back to Earth during this time, not to be fearful of them. To celebrate, people also adorn the graves of their ancestors with decorations and offer food to let them know that they haven’t forgotten them.

Actress Thora Hird (right, bending down) serving a witches brew punch at a Halloween party with fellow actorsKeystone/Getty Images

Why do we celebrate Halloween on October 31?

Halloween origin traces back to Gaelic and Celtic rituals dating back at least 2,000 years and it is from these we get the date and many of the ways we celebrate it.

The Gaelic festival of Samhain was traditionally held on the 1st of November to mark the official end of the harvest season and the beginning of winter. The celebrations always began the evening before, on the 31st of October, about halfway between the autumn equinox and winter solstice, says Sterling-Vete.

It also draws from the three-day pagan religious festival celebrated by the Celts around October 31 to honor the harvest and prepare for “the dark half of the year.”

History of Halloween

The ancients believed that on this day, the line between the living and the spiritual realm was blurred—meaning that ghosts from beyond could visit the living and monsters could find their way into people’s houses. Those celebrating aimed to ward off as much evil as possible. They held special rites to keep monsters, witches, and evil fairies at bay. They told tales about mythological heroes and the underworld. And they dressed up as monsters to ward off evil and to disguise themselves so they wouldn’t be kidnapped or consumed by actual monsters.

As Christianity became more popular, it added some of the Catholic holidays that fall right around Halloween, mixing the religious and pagan traditions. Why? To help further the transition from paganism to Catholicism. And it worked. All Souls’ Day embraced many of Samhain’s celebrations, including bonfires, parades, and costumes—though now people mainly dressed up as saints, angels, and devils.

Starting to sound familiar?

Halloween party, Southern California, 1928University of Southern California/Getty Images

Why do we celebrate Halloween?

Most of us aren’t afraid of being eaten by monsters nor do we feel the need to celebrate the harvest so why has Halloween stuck around? Halloween was a tough sell in early colonial America because of the Puritan’s strict religious beliefs, says Sterling-Vete. However, the holiday remained popular in the less-religious circles and as more and more Europeans arrived and mingled with the Native Americans, traditions evolved even further.

Halloween festivities meshed with autumn festivals and featured celebratory public events, singing and dancing, ghost stories, and pranks. But it wasn’t until the second half of the 19th century that Halloween really became popular in the United States. Why? Irish immigrants escaping the Potato Famine brought their ideas and traditions about Halloween along with them.

Speaking of terrifying tales, don’t miss these spooky stories that will keep you up at night.

How has Halloween changed to what it is today?

In this new whimsical context, Americans adopted the Celtic tradition of dressing up and transformed it into what we now know as trick-or-treating. By the 1930s, Halloween became almost completely secularized, while All Saints’ Day became more of a religious holiday. To this day, some devout people are strictly against celebrating October 31 as anything other than a religious day.

In the late 20th and early 21st centuries, Halloween became increasingly about commercialism and profits. In fact, Americans were expected to spend more than $8 billion on Halloween in 2020, according to the National Retail Federation.

Halloween traditions

So how is Halloween celebrated these days? Costumes, parties, toys, and candy are some of the most popular ways but there are lots of fun Halloween traditions. Here are some of our favorites:

Children carving Jack O'lanternBettmann/Getty Images

Carving Jack-o’-lanterns

Around 1895 it became traditional to carve Jack-o’-lanterns with ghoulish faces. They were originally carved from turnips (neeps) in the U.K. but pumpkins were substituted in the United States. Once carved, they were turned into lanterns and were carried by “guisers” to ward off any evil spirits and because in Christian folklore they represent a soul who has been denied entry into both heaven and hell, Sterling-Vete explains. Thankfully, we no longer carry them around with us (freeing up kids’ hands for more candy!).


Roaming bands of costumed kiddos going door-to-door begging for candy is probably the most time-honored Halloween tradition. This custom is directly related to what is called guising, because of the disguises or costumes worn to hide from evil spirits and can trace its origins back to 16th century Scotland, says Sterling-Vete. The phrase “trick or treat” is meant to jokingly scare the homeowners into giving treats or small toys.

Decorating with skulls, skeletons, and ghosts

Fake human bones are often displayed in silly ways on Halloween but they are a remnant of the ancients’ very serious fixation on the dead returning on October 31st—whether in spirit or with whatever is left of their mortal bodies. The imagery of the skull may also refer to the Christian tradition of Golgotha, or Calvary, the hill on which Jesus was crucified. “The skull serves as a reminder of death being ever-present amidst life, and of our short and transitory human existence,” says Sterling-Vete.

Avoiding black cats, scarecrows, witches

“Bogies” or evil spirits were a fixture in the Halloween origin and they live on today in the form of black cats, witches, and other things seen as omens or personifications of that evil. Scarecrows aren’t just used to scare birds away but evil spirits as well on Halloween. Start with these DIY Halloween decorations for the spookiest holiday ever.

children bobbing for apples at halloween partyBettmann/Getty Images

Bobbing for apples

The harvest traditions are almost forgotten in modern Halloween celebrations (or are incorporated into Thanksgiving in November) but this classic party game reminds us of our agricultural roots. Bobbing for apples was originally a Roman party game and not related to Halloween at all but rather true love. Apples were placed in water or hung from a string and each was given the name of a single man or woman. Then the unwed people would try to bite the apple of the one they wanted to marry.

Halloween parties

What’s more essential to a holiday celebration than a party? Halloween parties range in size from a family at home, to school-wide bashes with parades, to community extravaganzas. Parties are typically decorated in the Halloween colors of black, orange, and purple along with silly or spooky decor. Then it’s all about the entertainment. Put on a scary movie, dance, sing Karaoke, or try one of the Halloween party ideas if you’re stuck.

Halloween movies and haunted houses

You wouldn’t be amused if someone holding a bloody knife chased you down an alley on a regular day so why do people seek out terrifying experiences at Halloween time? Frightening situations release a flood of adrenaline, endorphins, and dopamine—powerful chemicals in your brain that increase feelings of excitement, alertness, and pleasure. In real life, these neurotransmitters would activate your body to fight or escape but these Halloween activities allow us to have those feelings but in a completely safe space.

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Charlotte Hilton Andersen
Charlotte Hilton Andersen, BS, MS, has been covering health, fitness, parenting, and culture for many major outlets, both in print and online, for 15 years. She's the author of two books, co-host of the Self Help Obsession podcast, and also does freelance editing and ghostwriting. She has appeared in television news segments for CBS, FOX, and NBC.