crampon

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A hinged pair of curved iron bars for raising heavy objects, such as stones or timber. Often used in the plural.
2. n. A spiked iron or steel framework that is attached to the bottom of a shoe or boot to prevent slipping when walking or climbing on ice and snow. Often used in the plural. Also called climbing iron.

Century Dictionary and Cyclopedia

1. n. An iron instrument fastened to the shoes of a storming party, to assist them in climbing a rampart.
2. n. An apparatus used in the raising of heavy weights, as timber or stones, and consisting of two hooked pieces of iron hinged together somewhat like double calipers.
3. n. In botany, an adventitious root which serves as a fulcrum or support, as in the ivy.

Wiktionary

1. n. An attachment to a shoe or boot that provides traction by means of spikes. Used for climbing or walking on slippery surfaces, especially ice.
2. n. botany An aerial rootlet for support in climbing, as of ivy.

GNU Webster's 1913

1. n. (Bot.) An aërial rootlet for support in climbing, as of ivy.
2. n. a device with pointed metal projections worn over the shoes to provide traction when walking over ice, or in mountaineering; -- usually used in the plural.
3. n. same as crampoon.

WordNet 3.0

1. n. an iron spike attached to the shoe to prevent slipping on ice when walking or climbing
2. n. a hinged pair of curved iron bars; used to raise heavy objects