BONUS: Halloween received its name because, around the year 800 A.D., the night of October 31 was called all hallow e'en, the night before the all hallow mass was recited, coinciding with which holiday?

The name of this spooky holiday is a direct linguistic link to its religious counterpart. "Halloween" is a Scottish contraction of "All Hallows' Eve," which translates to the evening before All Hallows' Day. The word "hallow" itself is an old English term for a holy person, or a saint, making All Hallows' Day another name for All Saints' Day, the Christian feast day celebrated on November 1st. The tradition of beginning a major Christian feast with a vigil the night before, such as with Christmas Eve, is why the celebration of saints began on the evening of October 31st.

The establishment of All Saints' Day on November 1st dates back to the 8th century when Pope Gregory III designated the date to honor all saints and martyrs. This move placed the Christian observance around the same time as the ancient Celtic festival of Samhain. Samhain marked the end of the harvest season and the beginning of winter, a time when the boundary between the world of the living and the world of the dead was believed to blur.

Many of the secular traditions we now associate with Halloween, such as wearing costumes to ward off spirits, are thought to have evolved from the customs of Samhain. Over centuries, the solemn religious observances of All Hallows' Eve and the folk traditions of Samhain merged, eventually giving rise to the modern, largely nonreligious celebration of Halloween that is known today.