anal fin

noun

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

Word History

First Known Use

1769, in the meaning defined above

Time Traveler
The first known use of anal fin was in 1769

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Dictionary Entries Near anal fin

Cite this Entry

“Anal fin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/anal%20fin. Accessed 12 Apr. 2024.

Kids Definition

anal fin

noun
: a single fin located on the lower back part of the body of a fish behind the excretory opening
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