All saints' day definition, a church festival celebrated November 1 in honor of all the saints; Allhallows. All Saints' Day commemorates the lives of past saints and includes asking for their prayers before God in heaven. The … All Saints Day is a Christian holiday of honoring Saints who have passed on to the afterlife usually observed on November 1st. See more. It is when the Catholic Church (and some Protestant churches) commemorate every saint, known and unknown. All Saints Day Definition and Meaning. In Eastern Churches, All Saints' Day is celebrated on the first Sunday following Pentecost. All Saints' Day definition is - November 1 observed in Western liturgical churches as a Christian feast in honor of all the saints. Wiki Learn what the Bible tells us about the saints of the Christian church. The eve of All Saints Day is known as All Hallows Eve, or Halloween. All Saints' Day is a church day celebrated by the Roman Catholic Church (and other Western Churches) on November 1. What is All Saints Day?