A term found in the United States Patent Act that relates to the concept of obviousness. An invention is obvious if it would have occurred to someone of ordinary skill in the art presented with the technical problem the invention purports to solve. In U.S. patent litigation, a considerable amount of dispute can center on what the hypothetical person of ordinary skill in art is, i.e., should it be a Ph.D. scientist, an ordinary technician, etc. A person of ordinary skill in the art is presumed to also be someone who would be familiar with all the prior art in the inventor’s field of endeavor and of common prior art solutions to the particular problem presented used in other fields.