bobsled

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

• noun A long metal racing sled with a steering mechanism that controls the front runners and a hand brake, usually raced down a curving ice-covered course by crews of two or four riders.
• noun A long sled made of two shorter sleds joined in tandem.
• noun Either of these two smaller sleds.
• intransitive verb To ride or race in a bobsled.

from The Century Dictionary.

• noun A sled consisting of a body resting on two short sleds called bobs, placed one behind the other.

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

• noun United States A short sled, mostly used as one of a pair connected by a reach or coupling; also, the compound sled so formed.
• noun a long racing sled (for 2 or more people), having two pairs of runners, with the front pair connected to a steering mechanism. They are usually raced one at a time down a steeply sloping path or specially constructed chute, with sharp banked curves, and attain high speeds.

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

• noun A sled used to go down a bob track.
• noun The sport of travelling down a bob track as fast as possible.
• noun A short sled, mostly used as one of a pair connected by a reach or coupling; the compound sled so formed.
• verb To ride a bobsled.

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

• verb ride a bobsled
• noun a long racing sled (for 2 or more people) with a steering mechanism
• noun formerly two short sleds coupled together