What do the fossil and rock words mean?
Each word here has a meaning quoted exactly from a U.S. government glossary, one plain sentence from us, and a picture of the thing itself.
Real photograph · 301131261/Shutterstock.com · Shutterstock Standard (free image collection, API) License
How these words are chosen
A word gets a page here only when three things exist for it. The first is a definition written by the U.S. Geological Survey or the National Park Service, whose words are free for anyone to copy. The second is a picture that really shows the thing, not a picture of something nearby. The third is at least one page on this site that uses the word, so the page has somewhere to send you next.
The definition is quoted word for word, because a definition in our own words would be us deciding what a word means. The sentence above it is ours, and it is only allowed to say the same thing more simply. Where a word is missing one of the three, it waits, and the list at the bottom of this page says which one.
The words
Real photograph · Map built from data: Smithsonian National Museum of Natural History (USNM V11910), CC0 · ArtEvent ET/Shutterstock.com · Tatiana Diuvbanova/Shutterstock.com · marekuliasz/Shutterstock.com · Map data: Scotese & Wright (2018), PALEOMAP PaleoDEMs — rendered by triassicwater.com · CC0-1.0 · Shutterstock Standard License · CC BY 4.0
Words still waiting
- Brachiopod. The National Park Service glossary defines it, and the words are held. No picture this site holds shows a brachiopod, so the page waits for one.
- Triassic. The National Park Service glossary defines it, and the words are held. No picture this site holds shows the Triassic itself, so the page waits for one.
- Jurassic. The National Park Service glossary defines it, and the words are held. No picture this site holds shows the Jurassic itself, so the page waits for one.
- Chalk. Neither government glossary this site can quote defines it yet.
- Deep time. Neither government glossary this site can quote defines it, or its cousin geologic time.
- Plate tectonics. The one government glossary found that defines it says its words were adapted from copyrighted dictionaries, so they are not ours to copy.
- Water cycle. The one definition found sits in a glossary that says it was compiled from several sources, including a state agency, so it cannot be shown to be free to copy.
Where the definitions come from
- U.S. Geological Survey, “Glossary of Geologic and Architectural Terms”, dated 07.21.97 on the page itself, https://pubs.usgs.gov/gip/acidrain/glossary.html, read . A work of the U.S. Government, in the public domain. Credit: U.S. Geological Survey.
- U.S. National Park Service, “Glossary of Paleontological Terms”, dated August 13, 2024 on the page itself, https://www.nps.gov/subjects/fossils/glossary-of-paleontological-terms.htm, read . A work of the U.S. Government, in the public domain. Courtesy of the National Park Service.
Where next
To see these words at work, start with How do we know what ancient Earth was like? or look through Which places were underwater?