The Arctic Ocean.

The nominal height of the surface of the oceans above which heights of geographical features and aircraft flight levels are measured.

A sea in British Isles, Europe, in the Atlantic. A sea between the islands of Great Britain and Ireland; bordered to the north by the North Channel and to the south by St George's Channel and the Celtic Sea.

Marine blue-green algae (cyanobacteria, actually brown coloured) of the genus Trichodesmium.

Any sessile tunicate, of the class Ascidiacea, which squirts water from two openings when touched; they are filter feeders

Frozen seawater.

A large but relatively shallow expanse of water within a landmass, sometimes connected to the ocean.

A body of water that separates three of the main islands of Japan, i.e. Honshu, Shikoku and Kyushu.

An extremely fine, rare and valuable fabric produced from the long silky filaments or byssus excreted by several molluscs (particularly Pinna nobilis, rough penshell) by which they attach themselves to the sea bed.

plural of sea lion