• Oceanography: The scientific study of the ocean and oceanic phenomena.

• Bathymetry: the measure of ocean depths and the charting of the shape or topography of the ocean floor.

• Sonar: An electronic depth sound mechanism sonar is an acronym for sound navigation and ranging. Sonar calculates ocean depth by recording the time it take for an energy pulse to reach the ocean floor and return.

• Submersible: a small underwater craft used for deep sea research.

• Continental Margin: the portion of the seafloor adjacent to the continents; it may include the continental shelf, continental slope, continental slope and continental rise.

• Continental Shelf: the gently sloping submerged portion of the continental margin, extending from the shoreline to the continental slope.

• Continental Slope: the steep gradient that leads to the deep ocean floor and marks the seawards edge of the continental shelf.

• Submarine Canyon: a seaward extension of a valley that that was cut on the continental shelf during a time when sea level was lower; a canyon carved into the outer continental rise, shelf, slope by turbidity currents.

• Turbidity Current: a down slope movement of dense, sediment –laden water created when sand and mud on the continental shelf and slope are dislodged and thrown into suspension.

• Continental Rise: the gently sloping surface at the base of the continental slope.

• Ocean Basin Floor: area of the deep-ocean floor between the continental margin and the oceanic ridge.

• Abyssal Plains: very level area of the deep-ocean floor, usually lying at the foot of the continental rise.

• Seamounts: an isolated volcanic peak that rises at least 1000 meters above the deep-ocean floor.

• Mid-Ocean Ridge: a continuous elevated zone on the floor of all the major ocean basin and varying in width from 1000 to 4000 kilometers; the rifts at the crests of edges represent divergent plate boundaries.

• Seafloor Spreading: the process by which plates tectonic produces new oceanic lithosphere at ocean ridges.

• Terrigenous Sediment: seafloor sediment derived from eroded rocks on land.

• Biogenous Sediment: seafloor sediment of biological origin, such as shells and skeletons of marine life.

• Calcareous Ooze: thick, common biogenous sediment produced by dissolving calcium carbonate shells.

• Siliceous Ooze: biogenous sediment composed of the silica-based shells of single –celled animals and algae.

• Hydrogenous Sediment: seafloor sediment consisting of minerals that crystallize from seawater; an important example is manganese nodules.

• Gas Hydrates: A gas, such as methane, trapped in a lattice-like structure of water molecules.

• Manganese Nodule: rounded lump of hydrogenous sediment scatter on the ocean floor, consisting mainly of manganese and iron and usually containing small amount of copper, nickel, and cobalt.