noun
fin
fihn
noun
1
One of the flat, wing-like parts on a fish or marine animal used for swimming and steering.
"The shark's dorsal fin sliced through the surface of the water."
2
A rigid, blade-like part sticking out from an aircraft, rocket, or vehicle to help it stay stable or steer.
"The tail fin keeps the aircraft flying straight."
3
A flipper worn on the foot for swimming or diving.
"She strapped on her fins before jumping into the pool."
How to Use Fin
Learner’s notesIn plain EnglishThe part of a fish (or a similar blade-like structure on planes, rockets, or diving gear) used for movement or stability.
Common pairings
dorsal fin
shark fin
a pair of fins
Word Forms
finned past tense, fins plural, fins plural, fins plural, fins singular
Study it as flashcards or scroll it in Flow — saved to your collection.
Test yourself on “fin”
A quick quiz — meaning, synonyms & usage
→
Fill the Gap
Can you complete this real example?
The shark's dorsal _____ sliced through the surface of the water.
Etymology
From Old English finn, from a Germanic root meaning "dorsal fin," ultimately tied to an ancient word for "backbone."