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K-T boundary
noun
: the transition between the Cretaceous and Tertiary periods of geologic time characterized by a mass extinction of many forms of life including the dinosaurs
also
: a geologic stratum marking this boundary
Examples of K-T boundary in a Sentence
Recent Examples on the Web
Kring was foundational in confirming the role of the Chicxulub crater’s impact event in the K-T boundary mass extinction.
—Anna Funk, Discover Magazine, 14 Nov. 2018
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Word History
Etymology
K (alternative for C as abbreviation for Cretaceous) + Tertiary
First Known Use
1983, in the meaning defined above
Dictionary Entries Near K-T boundary
Cite this Entry
“K-T boundary.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/K-T%20boundary. Accessed 15 Nov. 2024.
Kids Definition
K-T boundary
noun
: the transition between the Cretaceous and Tertiary periods of geologic time marked especially by the extinction of the dinosaurs
also
: a layer of rock marking this boundary
More from Merriam-Webster on K-T boundary
Britannica.com: Encyclopedia article about K-T boundary
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