am·​phi·​ox·​us | \ ˌam(p)-fē-ˈäk-səs How to pronounce amphioxus (audio) \
plural amphioxi\ ˌam(p)-​fē-​ˈäk-​ˌsī How to pronounce amphioxus (audio) \ or amphioxuses

Definition of amphioxus

: any of a genus (Branchiostoma) of lancelets broadly : lancelet

First Known Use of amphioxus

1837, in the meaning defined above

History and Etymology for amphioxus

borrowed from New Latin, genus name, from Greek amphi- amphi- + oxýs "sharp, keen" — more at oxygen

Note: The genus name Amphioxus was introduced by the English naturalist and bookseller William Yarrell (1784-1856) in A History of British Fishes, vol. 2 (London, 1836), pp. 468-72. The name alludes to the shape of the animal: "both ends pointed," as noted under "generic characters." Yarrell was unaware that the Italian zoologist Gabriele Costa had named the same genus Branchiostoma two years earlier (in Cenni zoologici, ossia descrizione sommaria delle specie nuove di animali, Naples, 1834, p. 49); by rules of taxonomy, the name Branchiostoma hence has priority over Amphioxus.

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The first known use of amphioxus was in 1837

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Cite this Entry

“Amphioxus.” Dictionary, Merriam-Webster, Accessed 27 Jan. 2021.

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More Definitions for amphioxus


am·​phi·​ox·​us | \ ˌam(p)-fē-ˈäk-səs How to pronounce amphioxus (audio) \
plural amphioxi\ -​ˌsī How to pronounce amphioxus (audio) , -​ˌsē How to pronounce amphioxus (audio) \ or amphioxuses

Medical Definition of amphioxus

 (Entry 1 of 2)

: a lancelet of the genus Branchiostoma broadly : lancelet



Medical Definition of Amphioxus (Entry 2 of 2)

taxonomic synonym of branchiostoma

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