Definition:
The upward force exerted by an object immersed in water. Something that is positively buoyant floats in water. Something that is negatively buoyant sinks in water. Neutrally buoyant is neither floating or sinking in water. An object becomes positively buoyant when it weighs less than the water it displaces and conversely is negatively buoyant when it weighs more than the water it displace.
Scuba divers carry weight to make them negatively buoyant and then add air to their BCD to become neutrally or positively buoyant. Air in the lungs also affects buoyancy.
Pronunciation: boy-ance-ee