In standards, bitumen emulsion is defined as a dispersion of bitumen droplets in water stabilized by an emulsifier system, with specified binder content, charge type, and performance properties. Definitions typically include classification by setting behavior, cationic or anionic nature, and residue properties after water removal. For procurement, the definition is tied to measurable acceptance criteria such as viscosity, residue, stability, sieve residue, demulsibility or breaking indicators, and pH. The technical definition is not just descriptive, it is enforceable through test methods and tolerances.