sibling species


: one of two or more species that are nearly indistinguishable morphologically

Example Sentences

Recent Examples on the Web This research suggested that T. rex should have two sibling species -- a more slender Tyrannosaurus regina (tyrant lizard queen) and the stouter and toothier Tyrannosaurus imperator (tyrant lizard emperor). Katie Hunt, CNN, 25 July 2022 The study team’s conclusion was that T. rex was not a single, unchanging dinosaur but may have had two equally terrifying sibling species. Katie Hunt, CNN, 28 Feb. 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sibling species.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

First Known Use

1940, in the meaning defined above

Time Traveler
The first known use of sibling species was in 1940

Dictionary Entries Near sibling species

Cite this Entry

“Sibling species.” Dictionary, Merriam-Webster, Accessed 1 Apr. 2023.

More from Merriam-Webster on sibling species

Love words? Need even more definitions?

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

What Did You Just Call Me?

  • brown chihuahua sitting on the floor with squinting eyes looking at the camera
  • Before we went to her house, Hannah told us her aunt was a flibbertigibbet.
True or False

Test your knowledge - and maybe learn something along the way.

Solve today's spelling word game by finding as many words as you can with using just 7 letters. Longer words score more points.

Can you make 12 words with 7 letters?