Latex - Emulsion , what is the difference ?

Emulsion is a general term. It refers to two immiscible fluids where one is suspended as small droplets in the other. Emulsions are typically white and creamy. Examples are milk, mayonaise, whipped cream, and you guessed it--latex. Latex is just a specific type of emulsion where an oil based paint or rubber compound is suspended in water and it can't cure until the water evaporates out. So it washes out like a water when wet, but it acts like an oil based or organic solid when dry--and typically is difficult to re-wet with water once the oil based droplets have connected together.