Baptism vs Christening
Baptism is a Christian ceremony in which a few drops of water are sprinkled on somebody or they are covered with water to welcome them into the Christian Church and often to name them. Baptism may include pouring water three times on the forehead of the person being inducted into the Church or having the person take a dip in a water tank.
The ritual of Baptism includes the believer disavowing his earlier life ‘without Christ’ to be ‘buried’ in water and washed away. It symbolizes a new birth through water.
Christening is when a baby is officially named and welcomed into the Christian Church. Christening may or may not be part of a Baptism ceremony. Adults who convert to Christianity are baptized and not christened.
Most Christians accept infant baptism including those following the Roman Catholic Church, Oriental Orthodoxy, Methodists etc but those groups that reject it include Baptists, all Old Time Missionary Baptists, Apostolic Christians, Disciples of Christ, Mennonites, Amish, etc.
While both Baptism and Christening are elaborate ceremonies, the latter is more so. It includes Blessing (the child is asked to believe in Jesus and repent his sins), Baptism (the ceremony or sacrament of admitting someone to the Church who agrees to believe in Jesus), Christening (the act of giving a name to the baby).
Baptism of children is often referred to as pedobaptism. Many people dispute the Christening as more than just the naming of the child claiming that the baby is too small to understand the concepts of sin and dedication to Jesus so it is more of a ceremony decided upon by the parents. They say that the child should be just given a name at the Christening ceremony and his baptism should follow later when he is able to understand what Christianity is all about.