Origin

This character combines "bird" (隹, at the top) with "hand" or "grasp" (又, at the bottom) to create an image of catching or holding a bird. From this concrete picture of capturing one bird, the character came to mean a single unit or one of a pair—eventually becoming a counter word for things that come in pairs or can be grasped individually, like the two wings of a bird, two fish, or two arrows. The meaning expanded to apply to any countable vessel or creature that might be caught or handled.