Earth's surface - the outermost level of the land or sea; "earthquakes originate far below the surface"; "three quarters of the Earth's surface is covered by water"layer - a relatively thin sheetlike expanse or region lying over or under another body of water, water - the part of the earth's surface covered with water (such as a river or lake or ocean); "they invaded our territorial waters"; "they were sitting by the water's edge" floor - the bottom surface of any a cave or lake etc. opening, gap - an open or empty space in or between things; "there was a small opening between the trees"; "the explosion made a gap in the wall" |