n. [ L. immersio; cf. F. immersion. ] 1. The act of immersing, or the state of being immersed; a sinking within a fluid; a dipping; as, the immersion of Achilles in the Styx. [ 1913 Webster ]

2. Submersion in water for the purpose of Christian baptism, as, practiced by the Baptists. [ 1913 Webster ]

3. The state of being overhelmed or deeply absorbed; deep engagedness. [ 1913 Webster ]

Too deep an immersion in the affairs of life. Atterbury. [ 1913 Webster ]

4. (Astron.) The dissapearance of a celestail body, by passing either behind another, as in the occultation of a star, or into its shadow, as in the eclipse of a satellite; -- opposed to emersion. [ 1913 Webster ]

Immersion lens, a microscopic objective of short focal distance designed to work with a drop of liquid, as oil, between the front lens and the slide, so that this lens is practically immersed. [ 1913 Webster ]

n. (Eccl.) One who holds the doctrine that immersion is essential to Christian baptism. [ 1913 Webster ]