ARM OF THE SEA. Lord Coke defines an arm of the sea to be where the sea or tide flows or reflows. Constable's Case, 5 Co. 107. This term includes bays, roads, creeks, coves, ports, and rivers where the water flows and reflows, whether it be salt or fresh. Ang. Tide Wat. 61. Vide Creek; Haven; Navigable; Port; Reliction; River; Road.