stirrup iron

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

• noun A stirrup.

from The Century Dictionary.

• noun The stirrup proper—that is, the metal loop in which the foot is placed, as distinguished from the leather strap which suspends it.
• noun An iron strip to hold the end of a beam or girder.

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

• noun support consisting of metal loops into which rider's feet go