pig iron

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Crude iron cast in blocks.

Century Dictionary and Cyclopedia

1. n. Iron in pigs, as it comes from the blast-furnace. See pig, 3.
2. n. A flat piece of iron, which is hung so as to be interposed between the fire and meat roasting, when it is desirable to retard the cooking.

Wiktionary

1. n. A type of crude iron shaped like a block, commonly used as an industrial raw material.

GNU Webster's 1913

1. n. the form in which cast iron is made at the blast furnace, being run into molds, called pigs.
2. n. cast iron in pigs, or oblong blocks or bars, as it comes from the smelting furnace. See Pig, 4.

WordNet 3.0

1. n. crude iron tapped from a blast furnace