submerge

Concise Oxford English Dictionary © 2008 Oxford University Press:
submerge/səbˈmɜːʤ/

▶verb

• 1 cause to be under water.

  ■ descend below the surface of water.

• 2 completely cover or obscure.

– derivatives
submergence noun,
submergible adjective.

– origin C17: from L. submergere, from sub- ‘under’ + mergere ‘to dip’.