The word Halloween is a shortened version of the phrase All Hallows' Eve or All Hallows' Evening ("The night of all saints", in Spanish).
On the first day of November, families around the world, from France to Mexico, celebrate All Saints' Day, a Christian festival typically marked with family gatherings and silent prayers to honor all saints.
In medieval England, the festival was known as All Hallows and took place on November 1. The eve is known as All Hallows' Eve, or Halloween, which is why it is celebrated every October 31. The day after All Saints' Day is All Souls' Day on November 2. These days were designated as a celebration of the saints and a time to pray for dead souls.