K-T boundary

noun

Definition of K-T boundary

: 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

Origin and Etymology of k-t boundary

K (alternative for C as abbreviation for Cretaceous) + Tertiary


Seen and Heard

What made you want to look up K-T boundary? Please tell us where you read or heard it (including the quote, if possible).

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

WORD OF THE DAY

the quality or state of being insatiable

Get Word of the Day daily email!

Test Your Vocabulary

Words for Summer: A Quiz

  • a-closeup-of-a-sunflower
  • Which of the following words means “of or relating to summer”?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Syn City

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!