"an emulsifying agent or apparatus," 1872, agent noun from emulsify.
"act of emulsifying; state of being emulsified," 1858, noun of action from emulsify.
"effort to equal or excel in qualities or actions that one admires in another or others; imitative rivalry," 1550s, from French émulation (13c.) and directly from Latin aemulationem (nominative aemulatio) "rivalry, emulation, competition," noun of action from past-participle stem of aemulari "to rival, strive to excel," from aemulus "striving, rivaling" (also as a noun, "a rival," fem. aemula), from Proto-Italic *aimo-, from PIE *aim-olo, suffixed form of root *aim- "copy" (from PIE root *aim- "to copy").
"a mixture of liquids insoluble in one another, where one is suspended in the other in the form of minute globules," 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" (from PIE root *melg- "to rub off; to milk"). The fat (butter) in milk is the classic example of an emulsion, drops of one liquid dispersed throughout another. Sense in photography is by 1840.
"to strive to equal or excel in qualities or actions," 1580s, a back-formation from emulation, or else from Latin aemulatus, past participle of aemulari "to rival." Related: Emulated; emulating; emulable; emulative.
1570s (adj.), "draining out;" 1610s (n.), in anatomy, "an emulgent vessel," from Latin emulgentem (nominative emulgens), present participle of emulgere "to milk out, drain out, exhaust," from assimilated form of ex "out" (see ex-) + mulgere "to milk" (from PIE root *melg- "to rub off; to milk"). Related: Emulgence.