A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution.
The most common solvent in everyday life is water. Most other commonly-used solvents are organic (carbon-containing) chemicals. These are called organic solvents. Solvents usually have a low boiling point and evaporate easily or can be removed by distillation, leaving the dissolved substance behind. To distinguish between solutes and solvents, solvents are usually present in the greater amount.
Solvents can also be used to extract soluble compounds from a mixture, the most common example being the brewing of coffee or tea with hot water. Solvents are usually clear and colorless liquids and many have a characteristic odor. The concentration of a solution is the amount of compound that is dissolved in a certain volume of solvent. The solubility is the maximal amount of compound that is soluble in a certain volume of solvent at a specified temperature. Common uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene), as paint thinners (e.g. toluene, turpentine), as nail polish removers and glue solvents (acetone, methyl acetate, ethyl acetate), in spot removers (e.g. hexane, petrol ether), in detergents (citrus terpenes), in perfumes (ethanol), and in chemical syntheses. The use of inorganic solvents (other than water) is typically limited to research chemistry and some technological processes.
For more, visit the Wikipedia entry for solvent, URL: http://en.wikipedia.org/wiki/Solvent