This biological meaning refers to the structures aquatic animals use for propulsion, steering, stability, and stopping.
The fish moved its fins rapidly.
Sharks have several distinct types of fins.
This meaning refers to broad footwear worn by swimmers and divers to increase propulsion in water.
The diver put on her mask and fins.
Long fins help swimmers move quickly underwater.
This engineering meaning refers to projecting surfaces that provide stability, steering, or aerodynamic control.
The rocket's fins keep it stable during flight.
Tail fins help control the aircraft.
This technical meaning refers to extended surfaces that increase the area available for heat transfer.
The motor has metal fins for cooling.
Dust reduced airflow between the heat-sink fins.
