A term commonly used for people who are seen by others doing alot of standing around at work on the production floor. Every time someone spots an "elbows", they are doing nothing but observing while leaning against something with their elbow. They lean so often on things in order to watch others work, that calisuses form on their elbows.
Damn, that guy Bob stands around so much that everyone calls him "Elbows" now. He leans up against anything all day long to make sure that it doesn't disappear. I believe that his purpose is to make sure that giant machinery doesn't grow feet and walk away while nobody is looking.