fin

fin — noun

1. a thin flat piece attached to a fish, aircraft, or vehicle that keeps it from ti

1.nounB1
Definition

a thin flat piece attached to a fish, aircraft, or vehicle that keeps it from tipping and helps it change direction

Example

The shark's dorsal fin cut through the water as it circled the boat.

dorsal fin — the fin on a fish's back

A small fin on the tail of the aircraft keeps it steady during flight.

Common collocations
  • dorsal fin
  • tail fin
  • vertical fin
  • pectoral fin
  • anal fin
Synonyms
  • appendage

    more general and technical; fin is specific to aquatic life and vehicles

  • stabilizer

    limited to aircraft and boats; does not apply to fish

  • flipper

    usually refers to a broad, flat limb of sea mammals (seals, turtles), not fish

Usage Note

Frequently used in compound nouns such as dorsal fin, tail fin, and vertical fin to name specific types.

2. a men's hairstyle in which the hair is brushed from the sides toward the middle

2.nounB2
Definition

a men's hairstyle in which the hair is brushed from the sides toward the middle of the head so that it stands up in a ridge like a fish's fin

Example

Jabari styled his hair into a fin by smoothing the sides and lifting the top.

style / shape hair into a fin

The barber showed Ilan how to create a fin using gel and a comb.

Common collocations
  • style a fin
  • create a fin
  • shape a fin
  • fin hairstyle
  • fin haircut
Synonyms
  • fauxhawk

    a softer, shorter version of a mohawk; similar but not identical to a fin

  • pompadour

    sweeps hair up and back rather than into a central ridge

Usage Note

An informal term; younger speakers may also call this a fauxhawk when the ridge is shorter.

3. a rubber or plastic shoe with a wide flat front that you wear on your foot to he

3.nounB1
Definition

a rubber or plastic shoe with a wide flat front that you wear on your foot to help you swim faster, especially underwater

Example

Anong put on her fins before jumping into the pool for training.

put on + fins

The diver's fins helped him move quickly through the strong ocean current.

Common collocations
  • a pair of fins
  • wear fins
  • put on fins
  • swim with fins
  • diving fins
Synonyms
  • flipper

    more common in British English; interchangeable in most contexts

Usage Note

Often used in the plural (fins) even when referring to one pair. Also called flippers, especially in British English.

Common Mistakes

I bought a fin for swimming.
I bought a pair of fins for swimming.
fins are always used in pairs, one for each foot.

4. a flat blade-like part fixed to the bottom or side of a boat, ship, or submarine

4.nounB2
Definition

a flat blade-like part fixed to the bottom or side of a boat, ship, or submarine that keeps it steady in the water and stops it from rolling too much

Example

The submarine's fin keeps it balanced when diving to great depths.

fin keeps [vehicle] balanced

Sahil checked the boat's fin for damage after it struck a rock near the shore.

Common collocations
  • boat fin
  • ship fin
  • submarine fin
  • fin stabilizer
  • roll fin
Synonyms
  • stabilizer

    broader term that includes fins but also other mechanical stabilising devices

  • keel

    the central structural spine of a boat's bottom, not a separate appendage

Usage Note

Distinguish from sense 1 (BALANCE & STEERING): sense 1 covers biological and aircraft fins; sense 4 is limited to water vessels.

fin — verb

fin — abbreviation

Word family

  • finned
    adjectiveB2
  • finless
    adjectiveC1
  • finning
    nounC1

Synonym discussion

Sense: noun/1

All four words refer to flat projecting parts that aid movement through air or water, but they differ in what they attach to and how they are used. A fin is the general term for a thin flat part on a fish, aircraft, or vehicle that helps with balance and steering. A flipper specifically describes the broad, flat limb of sea mammals such as seals and turtles, or a rubber swimming aid worn on the foot — it is not used for mechanical parts. A wing is the main lifting surface of a bird, insect, or aircraft; it generates lift rather than just stability, and is much larger relative to the body. A stabilizer is a mechanical device designed specifically to prevent rolling or swaying, most often found on boats and ships. For example: 'The shark's dorsal fin sliced through the water' (fin — aquatic animal), 'The plane's wing lifted smoothly during takeoff' (wing — aircraft lift), and 'The ship's stabilizer kept the passengers comfortable in rough waves' (stabilizer — mechanical anti-roll device).

fin ↗flipperwing ↗stabilizer

Common collocations

Nouns

  • fin shape
  • fin design
  • fin size
  • fin position
  • fin surface

Phrases

  • a pair of fins
  • dorsal fin
  • tail fin
  • vertical fin
  • fin stabilizer

Prepositions

  • with fins
  • without fins

Etymology

Proto-GermanicOld EnglishEnglish

The word fin comes from Old English finn, meaning 'fin of a fish,' with roots in the Proto-Germanic language (related to Dutch vin and German Finne). The original meaning was purely biological. As technology advanced, the word was extended to aircraft tail surfaces in the early 20th century, then to car body details, swim gear, and boat stabilisers. The verb senses developed from the noun in the 19th and 20th centuries.