A solution is a combination of different materials such that the mixture is evenly distributed. This means that one material dissolves evenly into the other, creating a homogeneous product. For example, sugar dissolves into water, creating a solution; meanwhile, sand does not dissolve in water, but instead settles to the bottom, so it does not create a solution.
Solutions can consist of different types of materials, including liquids, solids and gases. Metal alloys are a type of solid solution made by combining different types of metal to create a third, novel material. When one material is able to create a solution with another, it is called a "solvent" material.