Source : Webster's Revised Unabridged Dictionary (1913)

Submerge \Sub*merge"\, v. t. [imp. & p. p. {Submerged}; p. pr. &
   vb. n. {Submerging}.] [L. submergere, submersum; sub under +
   mergere to plunge: cf. F. submerger. See {Merge}.]
   1. To put under water; to plunge.

   2. To cover or overflow with water; to inundate; to flood; to
      drown.

            I would thou didst, So half my Egypt were submerged.
                                                  --Shak.

Submerge \Sub*merge"\, v. i.
   To plunge into water or other fluid; to be buried or covered,
   as by a fluid; to be merged; hence, to be completely
   included.

         Some say swallows submerge in ponds.     --Gent. Mag.

Source : WordNet®

submerge
     v 1: sink below the surface; go under or as if under water [syn:
          {submerse}]
     2: cover completely or make imperceptible; "I was drowned in
        work"; "The noise drowned out her speech" [syn: {drown}, {overwhelm}]
     3: put under water; "submerge your head completely" [syn: {submerse}]
     4: fill or cover completely, usually with water [syn: {inundate},
         {deluge}]