fin

1 of 4

noun (1)

ˈfin 

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

c

: flipper sense 1b

d

: any of the projecting ribs on a radiator or an engine cylinder

finlike

ˈfin-ˌlīk 

adjective

fin

2 of 4

verb

finned; finning

transitive verb

: to equip with fins

intransitive verb

1

: to show the fins above the water

2

: to move through water propelled by fins

fin

3 of 4

noun (2)

slang

: a 5-dollar bill

fin

4 of 4

abbreviation

1

finance; financial

2

finish

Examples of fin in a Sentence

Recent Examples on the Web

Verb

Even though efforts have been made internationally to reduce wasteful practices like finning and to set catch limits, global shark mortality remains high. —Melissa Cristina Márquez, Forbes.com, 7 Apr. 2025

Add a claustrophobic mask, a straw-like snorkel, fins that can weigh you down, plus waves and strong currents, can lead to a casual activity quickly turning into a high-intensity workout. —Jen Murphy, Outside Online, 2 Apr. 2025

Noun

While global attention has long focused on the shark fin trade, recent studies suggest that the meat trade has quietly overtaken fins in both volume and value. —Melissa Cristina Márquez, Forbes.com, 22 Apr. 2025

Snakeheads are often confused with a native species—the bowfin—but anglers can tell them apart by looking at the anal fin, which is much longer on a snakehead. —Sarah Kuta, Smithsonian Magazine, 18 Apr. 2025

Word History

Etymology

Noun (1)

Middle English finn, from Old English

Noun (2)

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

First Known Use

Noun (1)

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

Verb

1933, in the meaning defined at transitive sense

Noun (2)

1916, in the meaning defined above

Phrases Containing fin

• dorsal fin
• fin de siècle
• fin whale
• lobe-fin
• pectoral fin
• pelvic fin
• swim fin
• tail fin

Rhymes for fin

• been
• bin
• chin
• din
• djinn
• finn
• gin
• grin
• in
• kin
• linn
• linne

Kids Definition

fin

noun

ˈfin

1

: a thin process on the outside of an aquatic animal (as a fish or whale) used in propelling or guiding the body

2

: something shaped like a fin

finlike

-ˌlīk

adjective

finned

ˈfind

adjective