Some of these terms are often used interchangeably. This is incorrect and I will briefly explain the differences below.
A gulf is a large bay that is an arm of a sea or ocean. It is generally surrounded by more land, is more enclosed, and has a smaller opening than a bay, but not always. Gulfs make excellent harbors (AKA harbours) or trading centers because of their shape. An example is the Gulf of Mexico.
A bay refers to a body of the water that is partially surrounded by land and curves inwards. It is generally smaller than a gulf. It can be a part of an ocean or lake. One example is the Horseshoe Bay in Bermuda.
Technically, there are not many differences between gulfs and bays other than size and how enclosed they are from the ocean or sea. In essence, most gulfs are bays, but small bays are not categorized as gulfs. There are exceptions to these definitions such as the Bay of Bengal which is much larger than the Gulf of Mexico.
A port is a coastal facility where ships can load and unload commercial cargo. Ports are sometimes located in harbors but not always. Ports can also be located on the bank of a river or sea. An example is the Port of Los Angeles.
A harbor (or harbour) is a sheltered body of water where ships, boats, and barges can dock, often to get safety from severe weather. Harbors are differentiated from gulfs, bays, and coves in that those three describe geographical features, while a harbor is defined by its function. Ports often include one or more harbors. An example is the Honolulu Harbor in Hawaii.
A cove is a small bay with a restricted, narrow entrance. It is usually circular or oval in shape. Small, sheltered bays, narrow, inlets, creeks, and recesses in a coast are often considered coves. An example is Jobson’s Cove in Bermuda.
A marina is a dock usually with anchors and supplies for yachts and small boats. A marina differs from a port in that a marina does not handle large cargo ships or commercial freighters. Ports are for business, while marinas are usually for personal recreation. An example is the Corpus Christi Marina in Texas.
A wharf is a structure (usually a series of docks) on the shore of a harbor or on the bank of a river where ships may dock to load and unload passengers or cargo. It may also include warehouses, piers, or other facilities necessary for handling the ships. They sometimes have restaurants and shops. An example is Fisherman’s Wharf in San Francisco, California.
- The Shanghai port in China is the world’s busiest port.
- The Fisherman’s Wharf in San Francisco has over twelve million annual visitors.
- There are approximately 27,000 abandoned oil and gas wells beneath the Gulf of Mexico.
- DifferenceBetween.com – Difference between gulf and bay
- Quora.com – What are the differences among gulfs, bays, harbors, and coves?
- TreeHugger.com – 48 facts you should know about the Gulf of Mexico, from sunken ships to ancient corals