An emulsionis a mixture of two or more immiscible (un-blendable) liquids. Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion tends to imply that both the dispersed and the continuous phase are liquid. In an emulsion, one liquid is dispersed in the other (the continuous phase). Examples of emulsions include vinaigrettes, the photo-sensitive side of photographic film, milk, and cutting fluid for metal working.