What is a sacrament and how many are there?
The Catechism of the Catholic Church describes sacraments as "efficacious signs of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us. The visible rites by which the sacraments are celebrated signify and make present the graces proper to each sacrament. They bear fruit in those who receive them with the required dispositions." (1131)
They are part of the public prayer of the church with defined ritual words and actions where we encounter Christ (efficacious signs of grace) and are nourished and strengthened by God's gift of grace (divine life).
There are 7 sacraments:
Other ways we celebrate sacraments
Rite of Christian Initiation of Adults and children who have reached catechetical age (celebration of Baptism, Confirmation and Eucharist)
Viaticum, the last Sacrament of the Christian (Last Rites)