HOLDBACK

Hold″back′ (?), n. 1. 1. Check; hindrance; restraint; obstacle.
The only holdback is the affection . . . that we bear to our wealth. Hammond. 2. 2. The projection or loop on the thill of a vehicle. to which a strap of the harness is attached, to hold back a carriage when going down hill, or in backing; also, the strap or part of the harness so used.