A bay is a recessed, coastal body of water that directly connects to a larger main body of water , such as an ocean , lake , or another bay. A large bay is usually called a gulf, sea , sound , or bight. A cove is a type of smaller bay with a circular inlet and narrow entrance. A fjord is a particularly steep bay shaped by glacial activity.
Bays can be the estuary of a river , such as the Chesapeake Bay, an estuary of the Susquehanna River . Bays may also be nested within each other; for example, James Bay is an arm of Hudson Bay in northeastern Canada . Some large bays, such as the Bay of Bengal and the Hudson Bay, have varied marine geology .
The land surrounding a bay often reduces the strength of winds and blocks waves. Bays were significant in the history of human settlement because they provided safe places for fishing . Later they were important in the development of sea trade as the safe anchorage they provide encouraged their selection as ports.