Glossary of "Plant Biology (1st ed.)" by Graham et al. (2003)
- A region where all the water drains toward a common exit such as a stream.
Glossary of "Environmental Science: Earth as a Living Planet (2nd ed.)" by Botkin & Keller (1998)
- An area of land that forms the drainage of a stream or river. If a drop of rain falls anywhere within a watershed, it can flow out only through the same stream.
- 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.
- Graham, L. E., Graham, J. M. & Wilcox, L. W. 2003. Plant Biology. -xxxv + 497 pp. Pearson Education, Inc., Upper Saddle River.