What is it called when salt disappears into water?

The process of salt disappearing into water is called dissolution. Dissolution is the process in which a solid substance (in this case, salt) is dissolved into a liquid (in this case, water). The dissolved substance is called the solute (salt) and the liquid in which it is dissolved is called the solvent (water). The solute particles disperse evenly throughout the solvent, forming a homogeneous mixture.