How do you spell Buoyant

Available Definitions:
1)  v. t. & i. - Having the quality of rising or floating in a fluid; tending to rise or float; as, iron is buoyant in mercury.
2)  v. t. & i. - Bearing up, as a fluid; sustaining another body by being specifically heavier.
3)  v. t. & i. - Light-hearted; vivacious; cheerful; as, a buoyant disposition; buoyant spirits.