Stress is the consequence of the failure to aapt to change. It is, in medical terms, the consequence of the disruption of homeostasis through physical or psychological stimuli. Less simply: it's the condition that results when person-environment transactions lead someone to perceive a discrepancy, whether real or not, between the demands of a situation, on the one hand and, on the other, the resources of their biological, psychological or social systems. Stressful stimuli can be mental, physiological, anatomical or physical. The term 'stress' in this sense was coined by the Hungarian-Canadian endocrinologist Hans Selye in 1936.