: any of a subphylum (Cephalochordata) of small translucent marine primitive chordate animals that are fishlike in appearance and usually live partially buried on the ocean floor

called also amphioxus

Word History

First Known Use

circa 1836, in the meaning defined above

Time Traveler
The first known use of lancelet was circa 1836

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Cite this Entry

“Lancelet.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/lancelet. Accessed 24 Mar. 2025.

Kids Definition

: any of various small translucent marine animals that are related to the vertebrates, resemble fish, and usually live partly buried on the ocean floor

called also amphioxus

Medical Definition

: any vertebrate animal of the subphylum Cephalochordata

called also amphioxus

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