Final answer:
The earliest name for Halloween was All Hallows' Evening, derived from the Gaelic festival of Samhain. It later became known as Halloween.
Step-by-step explanation:
The earliest name for Halloween was All Hallows' Evening. It originated from the traditional Gaelic festival of Samhain, which marked the end of the harvest season and the beginning of winter. People believed that on this night, spirits and fairies could easily cross over into the mortal world, so they would light bonfires and dress in costumes to ward off evil spirits. Over time, All Hallows' Evening was shortened to Halloween.
Learn more about Origin and evolution of Halloween