noun A machine for clearing the beds of canals, rivers, harbors, etc.Fastened to the frame are iron handles, to which a rope or iron chain is attached. The net is usually composed of heavy twine, but sometimes of iron chainwork, and is attached to the frame by holes near the inner edges. As generally constructed, the frame is transversely oblong, generally about three times as long as wide, with straight ends and slightly inclined sides, having the outer edges sharp to serve as scrapers.

It consists principally of a frame of iron and a net which is attached to the frame. noun An apparatus for bringing up marine animals, plants, and other objects from the bottom of the sea for scientific investigation.noun Any instrument for bringing up or removing solid substances from under water by dragging on the bottom.transitive verb To coat (food) by sprinkling with a powder, such as flour or sugar.intransitive verb To come up with unearth.intransitive verb To bring up with a dredge.intransitive verb To clean, deepen, or widen with a dredge.noun An implement consisting of a net on a frame, used for gathering shellfish.noun Nautical A boat or barge equipped with a dredge.

noun Any of various machines equipped with scooping or suction devices and used to deepen harbors and waterways and in underwater mining.

From The American Heritage® Dictionary of the English Language, 5th Edition.

What does it mean to dredge something