Scientific terminology indicating multiple steps between a cause and effect. In actuality, the term is a glorified synonym for 'yadda yadda yadda'. It is also used as a filler statement when the speaker does not know how something occurs, but doesn't want to look stupid.
"I got blackout drunk at that party last year, and by the law of mass action, I gotta pay child support."
by Bernard Katz March 18, 2010