A sacrament is an outward sign of an inward grace. For example, in baptism, the outward sign is the pouring or washing with water. The inward grace is a relationship being opened up to a relationship with Jesus.
In the Catholic Church, there are seven sacraments: Baptism, Confirmation, the Eucharist, Penance, the Anointing of the Sick, Holy Orders and Matrimony.
...the seven sacraments touch all the stages and all the important moments of Christian life: they give birth and increase, healing and mission to the Christian's life of faith. There is thus a certain resemblance between the stages of natural life and the stages of the spiritual life. Catechism of the Catholic Church, 1210.