SUBMERSION Meaning of SUBMERSION in English sub ‧ mer ‧ sion /səbˈmɜːʃ ə n $ -ˈmɜːrʒ ə n/ BrE AmE noun [uncountable] the action of going under water, or the state of being completely covered in liquid Longman Dictionary of Contemporary English. Longman - Словарь современного английского языка. 2012