2. Submersion in water for the purpose of Christian baptism, as, practiced by the Baptists.
4. (Science: astronomy) 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. 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.