im·mer·sion 
(ĭ-mûrzhən, -shən)
(ĭ-mûrzhən, -shən)n.
1.
a. The act or an instance of immersing.
b. The condition of being immersed.
2. Baptism performed by totally submerging a person in water.
3. Astronomy The obscuring of a celestial body by another or by the shadow of another.