Dictionary Definition:

Solvent – “Able to dissolve other substances.”

Solute – “The minor component in a solution, dissolved in the solvent.”

Selected from OxfordDictionaries.com

Functional Definition: 

The solvent dissolves the solute. In reactions and solutions the solvent is usually a liquid that has the same polar/nonpolar relationship as the solute and breaks it down. Solvents can also help separate solutes based on polarity, solubility, and electronegativity.  The solute can be anything being broken down by the solvent, HCl, organic compounds, NaNO3, or sugars. Water is the most common solvent for polar molecule.