Sludge (?), n. [CF. Slush.] 1. Mud; mire; soft mud; slush. Mortimer. Tennyson.
2. Small floating pieces of ice, or masses of saturated snow. Kane.
3. (Mining) See Slime, 4.
Sludge hole, the hand-hole, or manhole, in a steam boiler, by means of which sediment can be removed.