Dictionary.com
Thesaurus.com

K/T boundary

British  

noun

  1. geology

    1. Cretaceous/Tertiary boundary: the time zone comprising the end of the Cretaceous and the beginning of the Tertiary periods

    2. ( as modifier )

      K/T boundary sediments
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Etymology

Origin of K/T boundary

C20 K and T , symbols for Cretaceous and Tertiary, respectively

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Centrosaurines went extinct millions of years before the chasmosaurines that were wiped out with the rest of the non-avian dinosaurs at the K/T boundary.

From Forbes • Jun. 4, 2015

But then came the stunning discovery by Luis and Walter Alvarez, father and son scientists, who while studying a clay layer marking the K/T boundary in Italy found striking amounts of iridium.

From Washington Post • Dec. 11, 2014

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.