It most commonly means a channel of water that lies between two land masses , but it may also mean a navigable channel through a body of water that is not navigable , for example because it is too shallow , or because it contains an unnavigable reef or archipelago . It most commonly refers to a channel of water that lies between two land masses , but it may also refer to a navigable channel through a body of water that is otherwise not navigable , for example because it is too shallow , or because it contains an unnavigable reef or archipelago .