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index fossil
noun
: a fossil usually with a narrow time range and wide spatial distribution that is used in the identification of related geologic formations
Examples of index fossil in a Sentence
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Pappas reports that Agnostus is a great index fossil.
—
Jason Daley, Smithsonian, 19 Sep. 2017
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Word History
First Known Use
1900, in the meaning defined above
Dictionary Entries Near index fossil
Cite this Entry
“Index fossil.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/index%20fossil. Accessed 11 Feb. 2025.
Kids Definition
index fossil
noun
: a fossil that is found over a relatively short span of geological time and can be used in dating formations in which it is found
More from Merriam-Webster on index fossil
Britannica.com: Encyclopedia article about index fossil
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