baptism - a Christian sacrament signifying spiritual cleansing and rebirth; "most churches baptize infants but some insist on adult baptism"sacrament - 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 affusion - the act of baptizing someone by pouring water on their head immersion - a form of baptism in which part or all of a person's body is submerged |