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

Love words?

You must — there are over 200,000 words in our free online dictionary, but you are looking for one that’s only in the Merriam-Webster Unabridged Dictionary.

Start your free trial today and get unlimited access to America's largest dictionary, with:

  • More than 250,000 words that aren't in our free dictionary
  • Expanded definitions, etymologies, and usage notes
  • Advanced search features
  • Ad free!

Dictionary Entries Near anal fin

analeptic

anal fin

analgesia

See More Nearby Entries 

Cite this Entry

“Anal fin.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/anal%20fin. Accessed 25 Nov. 2024.

Copy Citation

Share

Kids Definition

anal fin

noun
: a single fin located on the lower back part of the body of a fish behind the excretory opening
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See All

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Plural and Possessive Names: A Guide

The Difference Between 'i.e.' and 'e.g.'

Why is '-ed' sometimes pronounced at the end of a word?

What's the difference between 'fascism' and 'socialism'?
See All

Popular in Wordplay

See All

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments

10 Words from Taylor Swift Songs (Merriam's Version)

9 Superb Owl Words

15 Words That Used to Mean Something Different
See All

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
little chihuahua dressing like a turkey for thanksgiving
Is That Gratitude or Attitude? A Thanksgiving Quiz Decide which words express gratitude and which gi...