I
In phonetics , an emphasis given to a syllable of speech by making it louder than the rest of the word.
This emphasis may have no meaning; for example, Czech words are regularly stressed on the first syllable. It may, however, distinguish the meanings of similarly spelled but differently pronounced words; for example, permit is stressed on the first syllable as a noun and on the second as a verb. It may also be applied to a word to express its importance in a sentence. See also intonation .
II
In psychology, a state of bodily or mental tension resulting from factors that tend to alter an existent equilibrium.
Stress is an unavoidable effect of living and is an especially complex phenomenon in modern technological society. It has been linked to coronary heart disease , counseling or psychotherapy and medication.
III
In the physical sciences and engineering, the force per unit area within materials that arises from externally applied forces, uneven heating, or permanent deformation.
Normal stress refers to the stress caused by forces that are perpendicular to a cross-section area of the material. Shear stress arises from forces that are parallel to the plane of the cross section. Stress is expressed as the quotient of a force divided by an area.