[boi-uh
n-see, boo-yuhn-see] 
| 1. | the power to float or rise in a fluid; relative lightness. |
| 2. | the power of supporting a body so that it floats; upward pressure exerted by the fluid in which a body is immersed. |
| 3. | lightness or resilience of spirit; cheerfulness. |
| buoy·ance (boi'əns, bōō'yəns) n. Buoyancy. |
| buoyancy (boi'ən-sē) Pronunciation Key
The upward force that a fluid exerts on an object that is less dense than itself. Buoyancy allows a boat to float on water and provides lift for balloons. |