hydrospace

[ hahy-druh-speys ]
/ ˈhaɪ drəˌspeɪs /

noun

the regions beneath the surface of the oceans and seas.

Scientific definitions for hydrospace

hydrospace
[ hīdrə-spās′ ]

The regions beneath the ocean's surface, especially when considered as an area to be studied, as in marine mammal research or sonar mapping of the ocean floor.