-
- To save this word, you'll need to log in.
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
Examples are automatically compiled from online sources to
show current usage.
Read More
Opinions expressed in the examples do not represent those of Merriam-Webster or its editors.
Send us feedback.
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 25 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
Love words? Need even more definitions?
Merriam-Webster unabridged
Share