Immersion baptism
Immersion baptism (also known as baptism by immersion or baptism by submersion) is a method of baptism that is distinguished from baptism by affusion (pouring) and by aspersion (sprinkling), sometimes without specifying whether the immersion is total or partial, but very commonly with the indication that the person baptized is immersed completely. The term is also, though less commonly, applied exclusively to modes of baptism that involve only partial immersion (see Terminology, below)
Terminology
Baptism by immersion is understood by some to imply submersion of the whole body beneath the surface of the water.
Others speak of baptismal immersion as either complete or partial, and do not find it tautologous to describe a particular form of immersion baptism as "full" or "total".
Still others use the term "immersion baptism" to mean a merely partial immersion by dipping the head in the water or by pouring water over the head of a person standing in a baptismal pool, and use instead for baptism that involves total immersion of the body beneath the water the term "submersion baptism".