immersion

noun

1.
sinking until covered completely with water
submergence submerging submersion
2.
(astronomy) the disappearance of a celestial body prior to an eclipse
ingress
Antonym:
emersion
3.
complete attention; intense mental effort
absorption concentration engrossment
Derived from:
immerse
4.
a form of baptism in which part or all of a person's body is submerged
dipping dunking
5.
the act of wetting something by submerging it
dousing ducking submersion
Derived from:
immerse