Emulsifier- A chemical agent used to suspend one incompatible material in another. Generally, one end of an emulsifier molecule is soluble in water; the other end is soluble in organic solvent. This dual solubility helps hold the dissimilar liquids together.

Emulsion- A stable mixture of water and water insoluble materials in a finely divided state accomplished means of one or more surface-active agents such as soap or synthetic emulsifiers.

Emulsion Polymer- A polymer which exists in two phases; a continuous phase, which is usually water and a dispersed phase, which consists of polymer particles suspended in the continuous phase through the use of substances called emulsifiers.