A tubular duct or passage in bone or soft tissues.

An artificial open waterway used for transportation, waterpower, or irrigation.

A groove on the underside of a corona.

A long, narrow arm of the sea extending far inland, between islands, or between islands and the mainland.

A water-filled trench or conduit associated with a nuclear reactor, used for removing and sometimes storing radioactive objects taken from the reactor; the water acts as a shield against radiation.