ex·​os·​to·​sis | \ ˌek-(ˌ)sä-ˈstō-səs How to pronounce exostosis (audio) \
plural exostoses\ ˌek-​(ˌ)sä-​ˈstō-​ˌsēz How to pronounce exostosis (audio) \

Definition of exostosis

: a spur or bony outgrowth from a bone or the root of a tooth

Examples of exostosis in a Sentence

Recent Examples on the Web The dense growths are known as external auditory exostoses. Ashley Strickland, CNN, "Neanderthals got 'surfer's ear' too, study says," 14 Aug. 2019 Cold Water Love catching waves? Surfers and other cold water swimmers are prone to something called exostoses, or small bony growths in the ear canal that develop slowly over time and can prevent sound from getting in. Clare Thorp, Cosmopolitan, "5 Ways To Protect Your Hearing, Straight From the Professionals," 2 Aug. 2017 Riley was born with a genetic condition called hereditary multiple exostoses (HME), which causes irregular bone growth. George Diaz, OrlandoSentinel.com, "David Ragan gives teen thrill ride at Daytona during bittersweet weekend," 4 July 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'exostosis.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of exostosis

1736, in the meaning defined above

History and Etymology for exostosis

New Latin, from Greek exostōsis, from ex out of + osteon bone — more at ex-, osseous

Keep scrolling for more

Learn More about exostosis

Time Traveler for exostosis

Time Traveler

The first known use of exostosis was in 1736

See more words from the same year

Statistics for exostosis

Cite this Entry

“Exostosis.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/exostosis. Accessed 9 May. 2021.

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

Keep scrolling for more

More Definitions for exostosis


ex·​os·​to·​sis | \ ˌek-(ˌ)säs-ˈtō-səs How to pronounce exostosis (audio) \
plural exostoses\ -​ˌsēz How to pronounce exostosis (audio) \

Medical Definition of exostosis

: a spur or bony outgrowth from a bone or the root of a tooth

Other Words from exostosis

exostotic \ -​ˈtät-​ik How to pronounce exostosis (audio) \ adjective

More from Merriam-Webster on exostosis

Britannica.com: Encyclopedia article about exostosis

Comments on exostosis

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


Test Your Vocabulary

Star Wars Words Quiz

  • cu jedi training
  • The bounty portion of bounty hunters (such as Boba Fett) comes from a Latin word meaning
True or False

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


Anagram puzzles meet word search.

Love words? Need even more definitions?

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