Sacrament. A symbolic act, by which the church performs its commission as the body of Christ. It is more than a mere symbol; a sacrament represents something, but it also performs what it represents. So, for instance, if I was to say that I love you, my words would be a symbol of my love for you, but they would also perform what they represent - an act of loving you.
The seven major sacraments of the Catholic Church are Baptism, Confirmation, Reconciliation (also called Confession or Penance), Matrimony, Ordination (also called Holy Orders), Sacrament of the Sick (also called Extreme Unction or Last Rites) and Eucharist (also called Mass). Of these, Baptism and Eucharist are recognised as sacraments by the Anglican church, which also retains the other sacraments in different forms. Spectacular representations of the seven sacraments can be found on medieval fonts and benches.
At the Eucharist, the consecrated bread is usually referred to as the Blessed Sacrament. This was always reserved in medieval churches (that is to say, some was kept over at the end of Mass, and stored in the church to maintain a blessed presence, and for use in emergencies). The Blessed Sacrament is still reserved in all Catholic churches, and some Anglican churches have resumed the practice in the last 150 years, under the influence of the Oxford Movement. The sacrament is reserved in a tabernacle, a pyx or an aumbry.