29 CFR §1926.107

1. (a)Contaminant means any material which by reason of its action upon, within, or to a person is likely to cause physical harm.
2. (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.
3. (c)Lifeline means a rope, suitable for supporting one person, to which a lanyard or safety belt (or harness) is attached.
4. (d)O.D. means optical density and refers to the light refractive characteristics of a lens.
5. (e)Radiant energy means energy that travels outward in all directions from its sources.
6. (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.