cramp iron

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

• noun A bar, usually of iron, with right-angle bends at both ends, used for permanently holding together stones, timber, and other materials used in building.

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

• See cramp, n., 2.

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

• noun An iron bar, bent at right angles at each end, used to hold masonry together
• noun An arrangement of iron wedges inserted into a cavity to lift heavy stones; a lewis

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a strip of metal with ends bent at right angles; used to hold masonry together