A fin is a surface used to produce lift and thrust or to steer while traveling in water, air, or other fluid media. The word was first used for the limbs of fish, but it is now also used when describing other animal limbs and man-made devices.
The fins of fish are called:
- Dorsal fin on the back. Function: anti-roll stability.
- Caudal or tail fin: propulsion
- Pectoral fins (paired): steering
- Pelvic fins (paired): manoeuvering
- Anal fin: stability