safety belt

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

• noun A strap or belt worn as a safety precaution by a person working at great heights.

from The Century Dictionary.

• noun A belt made of some buoyant material or inflated to sustain a person in water; a life-belt; a safety-buoy. See life-preserver.

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

• noun A belt or strap that attaches a person to an immovable object for safety.

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

• noun belt attaching you to some object as a restraint in order to prevent you from getting hurt