Source : Webster's Revised Unabridged Dictionary (1913)

Submersion \Sub*mer"sion\, n. [L. submersio: cf. F. submersion.]
   1. The act of submerging, or putting under water or other
      fluid, or of causing to be overflowed; the act of plunging
      under water, or of drowning.

   2. The state of being put under water or other fluid, or of
      being overflowed or drowned.

Source : WordNet®

submersion
     n 1: sinking until covered completely with water [syn: {submergence},
           {submerging}, {immersion}]
     2: the act of wetting something by submerging it [syn: {immersion},
         {ducking}, {dousing}]