intensity

Etymology

intense + -ity. Cf. also Medieval Latin intensitas.

noun

1. The quality of being intense.
2. The degree of strength.
   The painting’s dislocated, unformed features are the very opposite of the hard, painted dolls of the other portrait, and, where they are dead and ready to topple, this unknown man’s eyes are full of intensity and life. 1980, Ann Jefferson, “[Character and the age of suspicion] Unforgettable figures: Portrait d’un inconnu and Le voyeur”, in The Nouveau Roman and the Poetics of Fiction, Cambridge, Cambs: Cambridge University Press, page 66
3. (physics) Time-averaged energy flux (the ratio of average power to the area through which the power "flows"); irradiance.
4. (optics) Can mean any of radiant intensity, luminous intensity or irradiance.
5. (astronomy) Synonym of radiance.
6. (geology) The severity of an earthquake in terms of its effects on the earth's surface, and buildings. The value depends on the distance from the epicentre, and is not to be confused with the magnitude.