By the fifth century, Augustine's definition of sacrament as an outward and visible sign of an inward and invisible grace became decisive. The church considered these two rites as sacred signs designed by God to indicate a divine reality, a reality that was included in and caused by the signs themselves.https://www.thegospelcoalition.org/essay/the-ordinances-of-the-church/
An ordinance is a Christian rite, associated with tangible elements (water; bread and wine), that is celebrated by the church of Jesus Christ. The term is closely associated with the word sacrament, which is an outward and visible sign of an inward and invisible grace.https://www.thegospelcoalition.org/essay/the-ordinances-of-the-church/