The pinyin for fin is qí.

Detailed definition:

The locomotor organ of fish, consisting of a membrane and spines, can be divided into pectoral, ventral, spine, anal, and caudal fins according to the part of the body where it is located.

Group definition:

1. Ventral fins: a pair of fins on the lower part of the body of a fish, located between the pectoral and anal fins. They are usually small and have a soft structure that serves to balance and stabilize the body posture. The ventral fins play an important function in the swimming process of fish, helping them to maintain a horizontal posture, steering and depth control.

2. Caudal fin: It refers to the position at the end of the fish's body and is a fin-like structure composed of muscle and bone. It is located at the back of the torso and is used to propel and control the swimming movement of the fish. The caudal fin usually shows a variety of forms, such as forked, rounded or fan-shaped, etc. Different forms of the caudal fin adapt to the swimming style and habits of different fish.

3. Fins: the raised structures on the body of a fish. The fins have a variety of functions, including balancing, maneuvering the swimming position, steering, providing stability, and controlling speed, etc. Different types of fins have different shapes. Different types of fins have different forms.

Example sentences for fins:

1, Fins are specialized structures on the bodies of fish, and by their swinging and unfolding, fish are able to dance gracefully through the water, displaying unparalleled swimming skill and agility that is breathtaking to behold.

2. In the depths of the ocean, a group of sharks chased a beautiful rainbow fish, admiring its dancing and flexible fins, as if the world had become more colorful because of this beautiful gesture.

3, in the blue sea, a group of fish like flying through, they elegantly swinging fins, swimming happily, as if the water dancers, the beautiful underwater world to the world, mesmerizing.

4, in the deep seabed, I saw a group of fish like dancing, they deftly swaying fins, sketching a charming pattern in the water, as if the nature for them to weave a gorgeous dance robe.

5, in the clear waters of the sea, a blue fish waving its long fins, elegantly shuttle between the coral reefs, for the sea brought endless beauty and vitality, as if a gorgeous painting unfolded in front of the eyes, let a person intoxicated.