plural noun

: a subclass or order of Cephalopoda including among existing forms only the genus Nautilus, differing from the remaining existing cephalopods in having four gills, four auricles to the heart, and a large chambered external shell, and including many extinct forms see ammonoidea , nautiloidea compare dibranchia

Word History


New Latin, from tetra- + -branchia

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Dictionary Entries Near Tetrabranchia

Cite this Entry

“Tetrabranchia.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Tetrabranchia. Accessed 3 Dec. 2023.

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