Jack-o’-lanterns, costumes, candy—the clues to the easiest game of associations ever. Yes, these are things we love about Halloween, a holiday we celebrate on the last day of the month of October. For many of us, Halloween is all about costume parties, carving pumpkins, watching horror movies, and trick-or-treating. In the Christian tradition, Halloween marks the beginning of a three-day observance known as Hallowtide, or the Hallowmass season—the time of the year when we celebrate those who are dead. The timing of the holiday coincides with an ancient Celtic holiday, Samhain, which marks the end of the harvest season and the beginning of winter.
While some are eager to point out the pagan roots in the way Halloween is celebrated today, others are equally eager to defend it as a purely Christian holiday. The word “Halloween” has roots in the Christian tradition. Hallow is an archaic word that evolved from the Old English word halgian. When used as a verb, it meant “to sanctify.” When used as a noun, it meant “holy person” or “saint.” The een portion of Halloween is a contraction of even, a word you might know as “eve,” which means “end of the day.” This is why Halloween is sometimes referred to as “All Hallows’ Eve” or “All Saints’ Eve.” “All Hallows Eve” was used for the first time in the sixteenth century. We can thank the eighteenth-century Scots for the contraction Halloween.
Since we’re already here talking about Halloween and words, let’s look at a few other Halloween expressions. Do you know why kids say “trick-or-treat,” or how the jack-o’-lantern got its name?
Trick-or-treating might have originated in the Celtic celebrations of Samhain. It’s said that people dressed in costumes that represented the souls of the deceased and were given offerings. The phrase “trick-or-treat” is a twentieth-century invention. When a kid says “trick-or-treat,” what she’s really saying is “give me candy (treat), or I’ll do some mischief (trick) on your property.” It’s extortion, albeit adorable extortion. You can’t have kids going around, knocking on doors, and saying “nice house you have there, it would be a shame if something happened to it.”
Jack-o’-lantern, originally, had nothing to do with a person named Jack, a lantern, or a carved pumpkin. Do you know what a will-o’-the-wisp is? In certain areas of the world, especially marshlands, bogs, or other wet areas where there’s a lot of decomposition going on, people sometimes see strange flickering lights. These lights can resemble a lamp, and the closer you get to it the more it fades. But by the time it disappears completely you might find yourself knee-deep in dirty swamp water, and possibly in peril. These lights have entered the folklore of cultures around the world, from the Americas to Asia, and each culture gives a different explanation for the origin of these lights. Jack-o’-lantern was one of the names given to this phenomenon in southwestern England and East Anglia. It’s short for “Jack of lantern,” where “of” actually means “with.” The first use of the term for a carved pumpkin lantern occurred in the nineteenth-century United States, and it’s been used ever since by kids and adults alike.
from Grammarly Blog https://www.grammarly.com/blog/halloween-etymology/