Definition of stress 1 : constraining force or influence: such as a : a force exerted when one body or body part presses on, pulls on, pushes against, or tends to compress or twist another body or body part; especially : the intensity of this mutual force commonly expressed in pounds per square inch b : the deformation caused in a body by such a force c : a physical, chemical, or emotional factor that causes bodily or mental tension and may be a factor in disease causation d : a state resulting from a stress; especially : one of bodily or mental tension resulting from factors that tend to alter an existent equilibrium job-related stress e : strain, pressure the environment is under stress to the point of collapse —Joseph Shoben 2 : emphasis, weight lay stress on a point 3 archaic : intense effort or exertion 4 : intensity of utterance given to a speech sound, syllable, or word producing relative loudness 5 a : relative force or prominence of sound in verse b : a syllable having relative force or prominence 6 : accent 5a