Evening of 31 October, immediately preceding the Christian feast of All Hallows or All Saints' Day. Customs associated with Halloween in the USA and the UK include children wearing masks or costumes, and ‘trick or treating’ – going from house to house collecting sweets, fruit, or money.
Halloween is associated with the ancient Celtic festival of Samhain, which marked the end of the year and the beginning of winter. It was believed that on the evening of Samhain supernatural creatures were abroad and the souls of the dead were allowed to revisit their former homes.
Halloween. (2018). In The Hutchinson Unabridged Encyclopedia with Atlas and Weather Guide. Helicon. https://search.credoreference.com/articles/Qm9va0FydGljbGU6NDg3NTI4?aid=107032