emulsion (n.) Look up emulsion at Dictionary.com
1610s, from French émulsion (16c.), from Modern Latin emulsionem (nominative emulsio), noun of action from past participle stem of emulgere "to milk out," from assimilated form of ex "out" (see ex-) + mulgere "to milk" (see milk (n.)). Milk is a classic instance of an emulsion, drops of one liquid dispersed throughout another.