Gulf: An arm of a sea or ocean partly enclosed by land; larger than a bay.

A sea is a large expanse of saline water connected with an ocean, or a large, usually saline, lake that lacks a natural outlet such as the Caspian Sea and the Dead Sea. The term is used colloquially as synonymous with ocean, as in "the tropical sea" or "down to the sea shore", or even "sea water" to refer to water of the ocean. Large lakes, such as the Great Lakes, are sometimes referred to as inland seas. Many seas are marginal seas, in which currents are caused by ocean winds; others are mediterranean seas, in which currents are caused by differences in salinity and temperature. The International Hydrographic Organization (IHO) is the world authority when it comes to defining seas. The current defining document is the Special publication S-23, Limits of Oceans and Seas, 3rd edition, 1953. The second edition dated back to 1937, and the first to 1928. A fourth edition draft was published in 1986 but so far several naming disputes (such as the one over the Sea of Japan) have prevented its ratification. A headland is an area of land adjacent to water on three sides. A bay is the reverse, rather an area of water bordered by land on three sides. Large headlands may also be called peninsulas; long, narrow and high headlands promontories. When headlands dramatically affect the ocean currents they are often called capes. A bay generally occupies an area wider than a fjord but smaller than a sound or gulf, either of which may include one or more bays