Glossary of Ecology (6th ed.) by Krebs (2009)
- a condition occurring in response to adverse external influences and capable of affecting the performance of an organism, for example, in plants in a drought.
Glossary of "Environmental Science: Earth as a Living Planet (2nd ed.)" by Botkin & Keller (1998)
- Force per unit area. May be compression, tension, or shear.
- Botkin, D. B. & Keller, E. A. 1998. Environmental Science: Earth as a Living Planet, 2nd ed. -xxxxii + 649 pp. John Wiley & Sons, Inc., New York.
- Krebs, C. J. 2009. Ecology, 6th ed. -xvi + 655 pp. Pearson Benjamin Cummings, San Francisco.