Noun

stress (countable and uncountable; plural stresses)

1. (countable, physics) The internal distribution of force per unit area (pressure) within a body reacting to applied forces which causes strain or deformation and is typically symbolised by σ
2. (countable, physics) externally applied to a body which cause internal stress within the body.
3. (uncountable) Emotional pressure suffered by a human being or other animal.

   Go easy on him, he's been under a lot of stress lately.

4. (uncountable, phonetics) The emphasis placed on a syllable of a word.

   Some people put the stress on the first syllable of “controversy”; others put it on the second.

5. (uncountable) Emphasis placed on words in speaking.
6. (uncountable) Emphasis placed on a particular point in an argument or discussion (whether spoken or written).

Synonyms

• (phonetics): accent, emphasis
• (on words in speaking): emphasis
• (on a point): emphasis

Stress is a term in psychology and biology, first coined in the 1930s, which has in more recent decades become a commonplace of popular parlance. It refers to the consequence of the failure of an organism – human or animal – to respond appropriately to emotional or physical threats, whether actual or imagined.

Stress symptoms commonly include a state of alarm and adrenaline production, short-term resistance as a coping mechanism, and exhaustion, as well as irritability, muscular tension, inability to concentrate and a variety of physiological reactions such as headache and elevated heart rate.