puddling

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

• noun Purification of impure metal, especially pig iron, by heating and stirring in an oxidizing atmosphere.
• noun Compaction of wet material, such as clay, in order to make a watertight paste.

from The Century Dictionary.

• noun In hydraul, engin., the operation of working plastic clay behind piling in a cofferdam, the lining of a canal, or in other situation, to prevent the penetration of water; also, the clay or other material used in this operation.
• noun The operation of transforming pig-iron into wrought-iron in a reverberatory furnace.

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

• noun The process of working clay, loam, pulverized ore, etc., with water, to render it compact, or impervious to liquids; also, the process of rendering anything impervious to liquids by means of puddled material.
• noun Puddle. See puddle, n., 2.
• noun (Metal.) The art or process of converting cast iron into wrought iron or steel by subjecting it to intense heat and frequent stirring in a reverberatory furnace in the presence of oxidizing substances, by which it is freed from a portion of its carbon and other impurities.
• noun a reverberatory furnace in which cast iron is converted into wrought iron or into steel by puddling.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun The action of making a puddle.
• noun The process of working clay, loam, pulverized ore, etc., with water, to render it compact, or impervious to liquids.
• noun canal engineering The act of lining a canal with puddle to make it watertight.
• noun metallurgy, historical The first true industrial process to produce steel from pig iron.
• noun A group of mallards (ducks).
• verb Present participle of puddle.