noun (1)
\ ˈfin How to pronounce fin (audio) \

Definition of fin

 (Entry 1 of 4)

1 : an external membranous process of an aquatic animal (such as a fish) used in propelling or guiding the body — see fish illustration
2 : something resembling a fin: such as
a : hand, arm
b(1) : an appendage of a boat (such as a submarine)
(2) : an airfoil attached to an airplane for directional stability
d : any of the projecting ribs on a radiator or an engine cylinder


finned; finning

Definition of fin (Entry 2 of 4)

transitive verb

: to equip with fins

intransitive verb

1 : to show the fins above the water
2 : to move through water propelled by fins


noun (2)

Definition of fin (Entry 3 of 4)

: a 5-dollar bill

Definition of fin (Entry 4 of 4)

1 finance; financial
2 finish

Other Words from fin

Noun (1)

finlike \ ˈfin-​ˌlīk How to pronounce fin (audio) \ adjective

First Known Use of fin

Noun (1)

before the 12th century, in the meaning defined at sense 1


1933, in the meaning defined at transitive sense

Noun (2)

1916, in the meaning defined above

History and Etymology for fin

Noun (1)

Middle English finn, from Old English

Noun (2)

Yiddish finf five, from Middle High German, from Old High German — more at five

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Time Traveler for fin

Time Traveler

The first known use of fin was before the 12th century

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Cite this Entry

“Fin.” Dictionary, Merriam-Webster, Accessed 24 Sep. 2021.

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More Definitions for fin


\ ˈfin How to pronounce fin (audio) \

Kids Definition of fin

1 : any of the thin parts that stick out from the body of a water animal and especially a fish and are used in moving or guiding the body through the water
2 : something shaped like an animal's fin the fins of a missile

More from Merriam-Webster on fin

Thesaurus: All synonyms and antonyms for fin

Nglish: Translation of fin for Spanish Speakers

Britannica English: Translation of fin for Arabic Speakers


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