The substance that dissolves in a solution is called the solute.

Here's a breakdown:

* Solution: A homogeneous mixture of two or more substances.

* Solute: The substance that dissolves in a solvent.

* Solvent: The substance that dissolves the solute.

For example, in a sugar water solution:

* Sugar is the solute because it dissolves.

* Water is the solvent because it dissolves the sugar.