emulsion (n.) Look up emulsion at Dictionary.com
1610s, from French émulsion (16c.), from Modern Latin emulsionem (nominative emulsio), from emulsus, past participle of emulgere "to milk out," from 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.