A body of water, such as a river, canal or lake, is navigable if it is deep, wide and calm enough for a water vessel to pass safely. Navigability is also referred to in the broader context of a body of water having sufficient under keel clearance for a vessel.

A body of water or waterbody is any significant accumulation of water on the surface of Earth or another planet. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles. A body of water does not have to be still or contained; rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water.