A sudden and rapid flow of tide in certain inlets of the sea; as the monstrous wave in the river Hooghly, called bahu by the natives, which rolls in with the noise of distant thunder at flood-tide. It occurs from February to November, at the new and full moon. Its cause has not been clearly defined, although it probably arises from the currents during spring-tides, acting on a peculiar conformation of the banks and bed of the river; it strikes invariably on the same part of the banks, majestically rolling over to one side, and passing on diagonally to the other with impetuous violence. The bore also occurs in England, near Bristol; and in America, in several rivers, but especially in the Bay of Fundy, where at the river Petticodiac the tide rises 76 feet. It also occurs in Borneo and several rivers in the East. (See hygre.) Also, the interior cavity of a piece of ordnance, generally cylindrical in shape, except when a part of it is modified into a chamber.