sacrament

n. (Christianity) religious ceremony or ritual believed to have been instituted by Jesus and viewed as a symbol of grace (such as baptism, matrimony, etc.); Holy Communion, holy bread

In Christian belief and practice, a sacrament is a rite, instituted by Christ, that mediates grace, constituting a sacred mystery. The root meaning of the Latin word sacramentum is to "make sacred". Views concerning both what rites are sacramental, and what it means for an act to be sacramental vary among Christian denominations and traditions.
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Noun
1. a formal religious act conferring a specific grace on those who receive it; the Protestant sacraments are baptism and the Lord's Supper; in the Roman Catholic Church and the Eastern Orthodox Church there are seven traditional rites accepted as instituted by Jesus: baptism and confirmation and Holy Eucharist and penance and holy orders and matrimony and extreme unction
(hypernym) religious ceremony, religious ritual
(hyponym) Holy Eucharist, Eucharist, sacrament of the Eucharist, Holy Sacrament, Liturgy, Eucharistic liturgy, Lord's Supper

n. sacrament

(v. t.)
To bind by an oath.
  

(n.)
The pledge or token of an oath or solemn covenant; a sacred thing; a mystery.
  

(n.)
The oath of allegiance taken by Roman soldiers; hence, a sacred ceremony used to impress an obligation; a solemn oath-taking; an oath.
  

(n.)
One of the solemn religious ordinances enjoined by Christ, the head of the Christian church, to be observed by his followers; hence, specifically, the eucharist; the Lord's Supper.