clei·​thrum | \ -rəm \
plural cleithra\ -​rə \

Definition of cleithrum

: a bone external to and beside the clavicle in the pectoral arch of some fishes, stegocephalians, and primitive reptiles

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

History and Etymology for cleithrum

borrowed from German, Latinization of Greek kleíthron, klêithron "bar fastening a door"

Note: Term introduced by the German biologist Karl/Carl Gegenbaur (1826-1903) in "Clavicula und Cleithrum," Morphologisches Jahrbuch, 23. Band, 1. Heft (September 10, 1895), p. 10 ("Ich nenne daher den bei den Fischen bisher als Clavicula geltenden Knochen Cleithrum, und belasse die Clavicula den pentadactylen Wirbelthiere in ihrem alterworbenen Namensrecht." - "Hence I give the name cleithrum to the bone that up to now has been regarded among fishes as the clavicule, and leave 'clavicle' with its long-acquired nomenclatural rights to the pentadactyl vertebrates.") Gegenbaur explains the name in a footnote by giving the Greek form kleîthron [sic] and the translation "Schloss, Riegel" ("lock, bolt").

Learn More About cleithrum

Dictionary Entries Near cleithrum




See More Nearby Entries 

Statistics for cleithrum

Cite this Entry

“Cleithrum.” Dictionary, Merriam-Webster, Accessed 27 Jun. 2022.

Style: MLA
MLACheck Mark Icon ChicagoCheck Mark Icon APACheck Mark Icon Merriam-WebsterCheck Mark Icon


Test Your Vocabulary

Odd Habits and Quirks

  • image1926873504
  • Which of the following best describes an easily irritated person?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

Universal Daily Crossword

A daily challenge for crossword fanatics.

Love words? Need even more definitions?

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