Im-mĕr'sion, n.

noun

n. [Lat. immersio, Fr. immersion, Sp. immersion, It. immersione.]

  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.
  2. The state of being overwhelmed or deeply engaged; absorption; deep engagedness. “Too deep an immersion in the affairs of life.” Atterbury.
  3. (Astron.) The disappearance of a celestial 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.