Among many Protestants, the word mediates would mean only that it is a visible Symbol, reminder or manifestation of invisible divine grace.
Roman Catholics, Eastern Orthodox Christians, the Oriental Orthodox, Assyrian Christians, members of the Anglican, United Methodist, and Old Catholic traditions, the Independent Catholic Churches and Lutherans hold that sacraments are not mere symbols, but rather, "signs or symbols which effect what they signify", that is, the sacraments in and of themselves, rightly administered, are used by God as a means to communicate grace to faithful recipients.
Christian churches and sects are divided regarding the number and operation of the sacraments, but they are generally held to have been instituted by Jesus. Sacraments are usually administered by the Clergy to a recipient or recipients, and are generally understood to involve visible and invisible components. The invisible component (manifested inwardly) is understood to be God's grace working in the sacrament's participants, while the visible (or outward) component entails the use of water, wine, or oil that is blessed or consecrated.
In addition to these seven, some Christian groups (Anabaptist and Brethren groups, in particular) consider foot washing to be a sacrament (see Gospel of John 13:14).
The seven sacraments accepted by Roman Catholicism are generally accepted by Eastern Orthodoxy and Oriental Orthodoxy, as well, but the latter traditions do not limit the number of sacraments to these seven, holding that anything the Church does as Church is in some sense sacramental.
The numeration, naming, and understanding of sacraments and the adoption of the remaining sacraments vary according to denomination.
Most Protestants consider only the "evangelical," or "dominical," sacraments - baptism and Communion - to be sacraments per se, understanding these to be the only such practices directly instituted by Jesus, as reported in the Gospels. They hold that the other five rites are not made sacraments by the New Testament. So while almost all Protestant churches have marriage ceremonies, and many have ordained Clergy and a ceremony conferring ordination, they consider these rites to be ordinances rather than sacraments.
As is often the case, views within the churches of the Anglican Communion vary. The '39 Articles' from the 1662 Book of Common Prayer (the root expression of all Anglican theology) declares that Baptism and Communion are the only two sacraments recognised in the English Church. Anglo-Catholics have always counted the sacraments at seven. Many others do now as well, with the other five considered lesser sacraments. The Catechism of the Episcopal Church in the United States of America states: "God does not limit himself to these rites; they are patterns of countless ways by which God uses material things to reach out to us."
Roman Catholics also have Sacramentals, acts of worship that differ from sacraments proper, but which are also means of grace. Items such as the Rosary or the various scapulars and holy medals issued by some Roman Catholic groups are counted among these sacramentals.
For the Eastern Orthodox and Oriental Orthodox Christian the term “Sacrament” is a Westernism that seeks to classify something that is rather difficult to classify. Preferably the term “Mystery” is used, the reason being that the “How it is possible” is unanswerable to human understanding. God touches us through material means such as water, wine, bread, oil, incense, candles, altars, icons, etc. How God does this is a Mystery. On a broad level, the Mysteries are an affirmation of the goodness of created matter, and are an emphatic declaration of what that matter was originally created to be. On a specific level, while not systematically enumerating Mysteries, the most profound Mystery is, without a doubt, the Eucharist, in which, by participation in the liturgy and receiving the consecrated bread and wine, understood to have become the body and blood of Christ itself, direct communion with God occurs. This perceived vagueness is considered by the Orthodox to be piety and respect for something profound and incomprehensible. Orthodox do not like to try to classify things to any great degree as this is seen to be a fruitless and unnecessary waste of time.
This approach is characteristic of Orthodox theology in general, and is often called "apophatic," meaning that any and all positive statements about God and other theological matters must be balanced by negative statements. For example, while it is correct and appropriate to say that God exists, or even that God is the only Being which truly exists, such statements must be understood to also convey the idea that God transcends what is usually meant by the term "to exist."
The Community of Christ, formerly known as the "Reorganized Church of Jesus Christ of Latter-Day Saints" practices eight official sacraments along with seeing other rites as sacramental in nature.
The Salvation Army does not practice formal sacraments for a variety of reasons, including a belief that it is better to concentrate on the reality behind the symbols; however, it does not forbid its members from receiving sacraments in other denominations .
Quakers do not practice formal sacraments, believing that all activities should be considered holy.