The ordinary, in Catholic liturgies, refers to the part of the Mass or of the canonical hours[1] that is reasonably constant without regard to the date on which the service is performed.
The ordinary of both the Eucharist and the canonical hours does, however, admit minor variations following the seasons (such as the omission of "Alleluia" in Lent and its addition in Eastertide).
The Apostles' Creed may substitute for it during Lent and Easter and at children's Masses, but some countries have received permission to recite it during the entire liturgical year.
The phrase Ite, missa est ("Go, it is the dismissal", referring to the congregation) is the final part of the Ordinarium in the post-Tridentine Mass.
The ordinary of the canonical hours consists chiefly of the psalter, an arrangement of the Psalms distributed over a week or a month.