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/
The name sacrament is derived from the Latin word, sacramentum, which was used in Latin translations of the Bible. The Greek New Testament uses the word μυστήριον (mystērion = mystery) to refer to matters that God once hid but now has revealed through the gospel (e.g., Rom 16:25-26; Eph 3:3-13; Col 1:24-27). The early church applied this term to its administration of baptism and the Lord's Supper, considering them to reveal a mystery of divine grace. When the Greek Bible was translated into Latin, μυστήριον (mystērion) became sacramentum, which could refer to a rite or an oath of allegiance.https://www.thegospelcoalition.org/essay/the-ordinances-of-the-church/