Solids separated from suspension in a liquid.

A residual semi-solid material left from industrial, water treatment, or wastewater treatment processes.

A sediment of accumulated minerals in a steam boiler.

A mass of small pieces of ice on the surface of a water body.

(uncountable, music) sludge metal

(intransitive, informal) To slump or slouch.

(intransitive) To slop or drip slowly.