Key Difference: Oceans are large bodies of water that exist on the Earth. An ocean is a body of saline water that composes a large part of a planet's hydrosphere. A gulf is a part of the ocean and is a large area of an ocean of a sea that is enclosed by land partially or on three sides.

Oceans and gulfs are large bodies of water. People are often confused as to why a part of the ocean is named as gulf, even though that body of water connects to the ocean. A gulf is a part of the ocean. Let’s look at how gulfs differ from oceans.

Oceans are large bodies of water that exist on the Earth. An ocean is a body of saline water that composes a large part of a planet's hydrosphere. Though for many years there were only four known oceans, in 2000, the International Hydrographic Organization added the Southern Ocean to the list. The five oceans in descending order of area are the Pacific, Atlantic, Indian, Southern (Antarctic), and Arctic Oceans. Approximately72% of the Earth is covered by water and though there are various different oceans, the waters comprise one global, interconnected body of salt water sometimes referred to as the World Ocean or global ocean.

Oceanographers divide the ocean into different zones depending on the present physical and biological conditions. The oceans are further categorized into zones by depth, light and other factors. The various different zones include pelagic zone (all open oceans regions), photic zone (surface to 200 meters down) and aphotic zone (depths exceeding 200 meters). The depth of an ocean ranges from 20,000 feet to 36,000 feet. The ocean currents also play a bit part in the Earth climate, by transferring heat from the tropics to the polar regions, and transferring warm or cold air and precipitation to coastal regions, where winds may carry them inland.

A gulf is a part of the ocean and is a large area of an ocean of a sea that is enclosed by land partially or on three sides. A gulf can also include a deep and wide chasm. It is often interchanged with the word bay; however bays are usually considered to be smaller than gulfs. A gulf is formed when the water from the ocean or a sea stops due to land. Due to constant eroding of the land, it forms a small deep cut in the land. The water than creates a passage of an inlet and becomes surrounded by land on three sides.

After the water becomes surrounded by three sides, it usually becomes calmer and does not move a lot like an ocean. Compared to oceans, gulfs are usually shallow. In order to be differentiated from a bay, the gulf must be surrounded by large landmasses, whereas a bay can be surrounded by small portions of land. A gulf can take on any shape and is limited to the land that surrounds it. Popular gulfs in the world include the Gulf of Mexico and the Persian Gulf.

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