The Collaborative International Dictionary of English v.0.48:
Submerse \Sub*merse"\, a. (Bot.) Submersed. [1913 Webster]WordNet (r) 3.0 (2006):
submerse v 1: sink below the surface; go under or as if under water [syn: submerge, submerse] 2: put under water; "submerge your head completely" [syn: submerge, submerse]