Sacraments
A sacrament is an encounter with Christ. It has a visible aspect (such as the pouring of water in Baptism) and it has an invisible or inner aspect (the action of Christ called grace). The name, sacrament, comes from a Latin word meaning sign.

A sacrament is a visible sign that has an invisible effect. Therefore each sacrament has a visible aspect that is seen by the senses, and an invisible aspect, referred to as grace, that makes people holy and empowers them to do good. Sacraments are religious ceremonies that use visible signs that give invisible grace from God.

These signs of grace were instituted by Christ and were entrusted to the Church. There are seven sacraments, and each has a definite purpose:
We are born:
We need nourishment:
We grow:
We need forgiveness:
We are sick and need healing:
We need family:
We need leaders in the Church:
Baptism
Eucharist
Confirmation
Reconciliation
Anointing of the Sick
Marriage
Holy Orders
The Catholic Catechism defines sacraments as “efficacious signs of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us through the work of the Holy Spirit.” (CCC #1131).

In summary, sacraments:
Are visible signs
Cause the invisible effect they signify
Convey grace, and the grace of each sacrament has a particular focus
Were instituted by Christ
Require a proper disposition in the recipient
Bring responsibilities and opportunities to the recipient

Catechism of the Catholic Church