E*mul"sion (?), n. [From L. emulgere, emulsum: cf. F. émulsion. See Emulge.] Any liquid preparation of a color and consistency resembling milk; as: (a) In pharmacy, an extract of seeds, or a mixture of oil and water united by a mucilaginous substance. (b) In photography, a liquid preparation of collodion holding salt of silver, used in the photographic process.

• a stable suspension of small droplets of one liquid in another with which it is immiscible
  
• (chemistry) a colloid in which both phases are liquid
  
• the coating of photosensitive silver halide grains in a thin gelatine layer on a photographic film