Section 1926.107 - Definitions applicable to this subpart(a)Contaminant means any material which by reason of its action upon, within, or to a person is likely to cause physical harm.(b)Lanyard means a rope, suitable for supporting one person. One end is fastened to a safety belt or harness and the other end is secured to a substantial object or a safety line.(c)Lifeline means a rope, suitable for supporting one person, to which a lanyard or safety belt (or harness) is attached.(d)O.D. means optical density and refers to the light refractive characteristics of a lens.(e)Radiant energy means energy that travels outward in all directions from its sources.(f)Safety belt means a device, usually worn around the waist which, by reason of its attachment to a lanyard and lifeline or a structure, will prevent a worker from falling.