CHAPTER 1 Definitions of stress

The first definition suggests that stress results from pressure. The greater the pressure the more likely that the recipient, whether a person or a load-bearing beam, will succumb. When the (external) stimulus becomes too great, (internal) collapse becomes inevitable. This definition focuses on external sources of stress and encapsulates well its cumulative nature. Adding one more ounce to the weight on the beam may make little difference to the total load but may yet be enough to cause it to break. This is the main definition still provided in the Oxford English Dictionary: "to subject (a material thing, a bodily organ, a mental faculty) to stress or strain; to overwork, fatigue."