The Collaborative International Dictionary of English v.0.48:
Buff \Buff\, a.
1. Made of buff leather. --Goldsmith.
2. Of the color of buff.
Buff coat, a close, military outer garment, with short
sleeves, and laced tightly over the chest, made of buffalo
skin, or other thick and elastic material, worn by
soldiers in the 17th century as a defensive covering.
Buff jerkin, originally, a leather waistcoat; afterward,
one of cloth of a buff color. [Obs.] --Nares.
Buff stick (Mech.), a strip of wood covered with buff
leather, used in polishing.