A sacramental is a material object or action (in Latin sacramentalia) ritually blessed by a priest to signal its association with the Sacraments and so to incite reverence during acts of worship. They are recognised by the Roman and Eastern Catholic churches, the Eastern and Oriental Orthodox churches, the Church of the East, as well as certain Anglican, Independent Catholic and Old Catholic, Lutheran churches, and Methodist churches.
Holy water, for example, is a sacramental that believers use to recall their baptism; other common sacramentals include blessed candles (often given to churchgoers on Candlemas), blessed palms (given away at churches on Palm Sunday), blessed ashes (placed on believers' foreheads on Ash Wednesday services), a cross necklace (often taken to be blessed by a pastor before daily use), blessed salt, and holy cards, as well as Christian art, especially a crucifix. Apart from those worn daily, such as a cross necklace or devotional scapular, sacramentals are often kept on home altars in Christian households.
As an adjective, sacramental means "of or pertaining to sacraments".
The Biblical basis for the use of sacramentals is that Jesus used a form of sacramentals himself; for example, when Christ healed a blind man, he made a mud paste that He put over the eyes of the man, before telling him to wash in the Pool of Siloam.
The Catholic Church currently defines sacramentals as "sacred signs which... signify effects, particularly of a spiritual nature, which are obtained through the intercession of the Church. By them men are disposed to receive the chief effect of the sacraments, and various occasions in life are rendered holy." 
Sacramentals do not confer the grace of the Holy Spirit in the way that the sacraments do, but by the Church's prayer, they prepare one to receive grace and dispose a person to cooperate with it. "For well-disposed members of the faithful, the liturgy of the sacraments and sacramentals sanctifies almost every event of their lives with the divine grace which flows from the Paschal mystery of the Passion, Death, and Resurrection of Christ. From this source all sacraments and sacramentals draw their power."
Rosary beads, scapulars, medals and religious images are more accurately termed devotional articles; non-liturgical prayers such as the rosary, the stations of the cross, litanies, and novenas are called popular devotions or "expressions of popular piety".
Pentecostal theologian Mark Pearson states that the Bible speaks of sacramentals, sometimes referred to as points of contact, such as blessed prayer cloths (Acts 19:11-19:12) and holy oil (James 5:14). He states that God is the source of healing and that Pentecostal clergy "can confidently offer prayer, administer the various sacramentals, and lay hands on the sick".
Clara Saraiva, Peter Jan Margry, Lionel Obadia, Kinga Povedák, José Mapril