sponge

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

• noun Any of numerous aquatic, chiefly marine filter-feeding invertebrate animals of the phylum Porifera, characteristically having a porous skeleton composed of fibrous material or siliceous or calcareous spicules and often forming colonies attached to an underwater surface.
• noun A piece of the absorbent skeleton of certain of these organisms, or a piece of plastic or another material that is similar in absorbency, used for cleaning, bathing, and other purposes.
• noun Metal in a porous, brittle form, as after the removal of other metals in processing, used as a raw material in manufacturing.
• noun A gauze pad used to absorb blood and other fluids, as in surgery or the dressing of a wound.
• noun A small absorbent contraceptive pad that contains a spermicide and is placed against the cervix of the uterus before sexual intercourse.
• noun Dough that has been or is being leavened.
• noun A light cake, such as sponge cake.
• noun Informal One who habitually depends on others for one's own maintenance.
• noun Slang A person who drinks large amounts of alcohol.
• intransitive verb To moisten, wipe, or clean with a sponge or cloth.
• intransitive verb To remove or absorb with a sponge or cloth.
• intransitive verb To apply or daub with a sponge.
• intransitive verb Informal To obtain free, as by begging or freeloading.
• intransitive verb To harvest sponges.
• intransitive verb Informal To obtain something such as food or money by relying on the generosity of others.

from The Century Dictionary.

• noun Any absorbent material employed to take up the blood and other fluids in surgical operations.
• To cleanse or wipe with a sponge: as, to sponge the body; to sponge a slate or a cannon.
• To wipe out with a sponge, as letters or writing; efface; remove with a sponge; destroy all traces of: with out, off, etc.
• Specifically To dampen, as in cloth-manufacturing.
• To absorb; use a sponge, or act like a sponge, in absorbing: generally with up: as, to sponge up water that has been spilled.
• To gain by sycophantic or mean arts.
• To drain; harass by extortion; squeeze; plunder.
• In baking, to set a sponge for: as, to sponge bread.
• To gather sponges where they grow; dive or dredge for sponges.
• To live meanly at the expense of others; obtain money or other aid in a mean way: with on.
• noun A fixed aquatic organism of a low order, various in form and texture, composed of an aggregate of amœbiform bodies disposed about a common cavity provided with one or more inhalent and exhalent orifices (ostioles and oscules), through which water pours in and out.
• noun The fibrous framework of a colony of sponge-animalcules, from which the animalcules themselves have been washed out, and from which the gritty or sandy parts of the colony, if there were any, have been taken away. See skeleton, 1 .
• noun Any sponge-like substance.
• noun A tool for cleaning a cannon after its discharge.
• noun Figuratively, one who or that which absorbs without discrimination, and as readily gives up, when subjected to pressure, that which has been absorbed.
• noun One who persistently lives upon others; a sycophantic or cringing dependent; a hanger-on for the sake of maintenance; a parasite.
• noun In the manège, the extremity or point of a horseshoe answering to the heel.
• noun The coral, or mass of eggs, under the abdomen of a crab.

from the GNU version of the Collaborative International Dictionary of English.

• intransitive verb To suck in, or imbibe, as a sponge.
• intransitive verb Fig.: To gain by mean arts, by intrusion, or hanging on.
• intransitive verb To be converted, as dough, into a light, spongy mass by the agency of yeast, or leaven.
• transitive verb To cleanse or wipe with a sponge; ; to wet with a sponge.
• transitive verb To wipe out with a sponge, as letters or writing; to efface; to destroy all trace of.
• transitive verb Fig.: To deprive of something by imposition.
• transitive verb Fig.: To get by imposition or mean arts without cost.
• noun (Zoöl.) Any one of numerous species of Spongiæ, or Porifera. See Illust. and Note under spongiæ.
• noun The elastic fibrous skeleton of many species of horny Spongiæ (Keratosa), used for many purposes, especially the varieties of the genus Spongia. The most valuable sponges are found in the Mediterranean and the Red Sea, and on the coasts of Florida and the West Indies.
• noun One who lives upon others; a pertinacious and indolent dependent; a parasite; a sponger.
• noun Any spongelike substance.
• noun Dough before it is kneaded and formed into loaves, and after it is converted into a light, spongy mass by the agency of the yeast or leaven.
• noun Iron from the puddling furnace, in a pasty condition.
• noun Iron ore, in masses, reduced but not melted or worked.
• noun (Gun.) A mop for cleaning the bore of a cannon after a discharge. It consists of a cylinder of wood, covered with sheepskin with the wool on, or cloth with a heavy looped nap, and having a handle, or staff.
• noun (Far.) The extremity, or point, of a horseshoe, answering to the heel.