Immersion

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.

Submersion in water for the purpose of Christian baptism, as, practiced by the Baptists.

The state of being overhelmed or deeply absorbed; deep engagedness.

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.

(astronomy) the disappearance of a celestial body prior to an eclipse

complete attention; intense mental effort