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. [ 1913 Webster ]