(Latin: free day)
In ancient Rome a day kept as a holiday. It is a liturgical designation for weekdays on which no ecclesiastical feast is celebrated; also for all weekdays divided according to rank, into privileged (Ash Wednesday, days of Holy Week, days within the octave of Easter and Pentecost), which exclude commemoration of all feasts; major (days of Advent and Lent, ember days, Rogation Monday), which must at least be commemorated in the Mass and Office of the day; and minor. From feria, the term fair, or fair day, is derived.