Merriam-Webster Collegiate Dictionary - stress

 I. noun  Etymology: Middle English ~e ~, di~, short for de~e — more at di~  Date: 14th century  1. constraining force or influence: 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 ~; especially one of bodily or mental tension resulting from factors that tend to alter an existent equilibrium job-related ~  e. strain, pressure the environment is under ~ to the point of collapse — Joseph Shoben  2. emphasis, weight lay ~ 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 6a  II. verb  Date: 1545  transitive verb  1. to subject to physical or psychological ~ ~ing the equipment this traffic is ~ing me out  2. to subject to phonetic ~ ; accent  3. to lay ~ on ; emphasize ~ed the importance of teamwork  intransitive verb to feel ~ ~ing about the big exam — often used with out