noun 1.the theory that every complex phenomenon, especially in biology or psychology, can be explained by analyzing the simplest, most basic physical mechanisms that are in operation during the phenomenon.
2.the practice of simplifying a complex idea, issue, condition, or the like, especially to the point of minimizing, obscuring, or distorting it.
Related forms re·duc·tion·ist, noun, adjective
re·duc·tion·is·tic, adjective