What is buayancy?

Answer 1

I think you mean buoyancy?

It's the power to float or rise in a fluid; relative lightness.

Answer 2

Buoyancy is the ability of an object to float in a fluid, like water or air, due to the upward force exerted by the fluid on the object. It depends on the object's density and the density of the fluid it is placed in. Objects that are less dense than the fluid will float, while those that are more dense will sink.