anal fin

noun

Definition of anal fin

in fishes
: a median unpaired fin on the lower posterior part of the body behind the vent and sometimes confluent with the caudal fin — see fish illustration

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First Known Use of anal fin

1769, in the meaning defined above

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The first known use of anal fin was in 1769

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Cite this Entry

“Anal fin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/anal%20fin. Accessed 16 Jun. 2021.

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