- hydrologythe study of the distribution, movement, and properties of water in nature
- 学 學 nounaffixbranch of learning(bound form) a subject or branch of study; often used as a suffix for -logy, -ics, or -science
- 者 affixnoun-er(bound form) used after a verb, adjective, or noun to represent the person or thing performing an action or possessing a quality; translates as "-er", "-ist", or "one who"