An arrow is a fin-stabilized projectile launched by a bow. A typical arrow usually consists of a long, stiff, straight shaft with a weighty arrowhead attached to the front end, multiple fin-like stabilizers called fletchings mounted near the rear, and a slot at the rear end called a nock for engaging the bowstring. A container or bag carrying additional arrows for convenient reloading is called a quiver.
Traditional target arrow (top) and replica medieval arrow (bottom)
Modern arrow with plastic fletchings and nock
Warring States bronze arrowheads
African bow and arrows in a quiver
A fin is a thin component or appendage attached to a larger body or structure. Fins typically function as foils that produce lift or thrust, or provide the ability to steer or stabilize motion while traveling in water, air, or other fluids. Fins are also used to increase surface areas for heat transfer purposes, or simply as ornamentation.
Fish get thrust moving vertical tail fins from side to side.
Cetaceans get thrust moving horizontal tail fins up and down.
Stingrays get thrust from large pectoral fins.
Ship propeller