flotation

Short definition from Wiktionary

Noun

1. 1
   A state of floating, or being afloat.
2. 2
   The ability (as of a tire or snowshoes) to stay on the surface of soft ground or snow.
3. 3
   A process of separating minerals by agitating a mixture with water and detergents etc; selected substances being carried to the surface in air bubbles.
4. 4
   The launching onto the market of a tranche of stocks or shares, usually a new issue.