The phrase "warm seawater" refers to water from the ocean that is not cold, but rather at a higher temperature, which can feel pleasant on the skin or when swimming. Full definition
White - sand beaches stretch around the island with warm seawater to one side and a line of coconut trees behind. (flywithshaunak.com)
The shape of the cavity beneath the tongue controls the access of deep warm seawater to the base of the glacier. (lablit.com)
As runoff from melting glaciers increases and warming seawater expands, sea level could rise as much as six feet, inundating low - lying coastal areas and islands. (discovermagazine.com)