Disperse Phase and Dispersion Medium
The material body which is present in a state of fine discrete particles is called the disperse phase and the continuous medium in which the discrete particles are present is called the dispersion medium. Disperse Phase is particulate solid or liquid phase of a colloid distributed within a fluid. Dispersion Medium is the continuous medium, such as a gas, liquid, or solid, in which a disperse phase is distributed. Also called external phase.
For example, in potable gold (this is a suspension of gold particles in aqueous medium and is used in medicine), gold is present as discrete particles and constitutes the disperse phase, water is the dispersion medium. Yet another example is milk where small fat globules are present as discrete particles in water. Here the fat globules are the disperse phase and water the dispersion medium. In butter water is the disperse phase and fat the dispersion medium.