Glossary

417 words used in the labs.

Find a term from the labs, understand the process behind it, and see how it appears in the landscape. Each entry connects an explanation with a real observation and a model you can explore.

Term

Swallow hole

Also written: Swallet / sinking stream

An opening where a surface stream enters underground drainage, usually in karst. A doline or sinkhole is a depression and need not contain a sinking stream.

What to look for

Stream Passage Pot, Ingleborough, North Yorkshire. This entrance belongs to the Gaping Gill karst drainage system, where surface water enters underground passages.

Related labs

Karst →

A rocky opening in grassy limestone terrain at Stream Passage Pot in the Gaping Gill cave system.

Explore further with USGS water glossary · USGS volcano glossary · NPS glacial geology · NASA Earth facts. Photograph acknowledgements are collected on the Image credits page.