difference between colloidal solution & emulsion

An emulsion is a mixture of two or more liquids that are normally immiscible (nonmixable or unblendable). 
Emulsions are part of a more general class of two-phase systems of matter called colloids. Although the terms colloid and emulsion are sometimes used interchangeably, emulsion should be used when both the dispersed and the continuous phase are liquids. 
In an emulsion, one liquid (the dispersed phase) is dispersed in the other (the continuous phase).
The word "emulsion" comes from the Latin word for "to milk", as milk is an emulsion of milk fat and water, among other components.
Two liquids can form different types of emulsions. As an example, oil and water can form, firstly, an oil-in-water emulsion, where the oil is the dispersed phase, and water is the dispersion medium. Secondly, they can form a water-in-oil emulsion, where water is the dispersed phase and oil is the external phase. Multiple emulsions are also possible, including a "water-in-oil-in-water" emulsion and an "oil-in-water-in-oil" emulsion.
Emulsions, being liquids, do not exhibit a static internal structure. The droplets dispersed in the liquid matrix (called the “dispersion medium”) are usually assumed to be statistically distributed.
A colloid is a substance microscopically dispersed throughout another substance.
The dispersed-phase particles have a diameter of between approximately 2 and 500 nanometers. Such particles are normally invisible in an optical microscope, though their presence can be confirmed with the use of an ultramicroscope or an electron microscope. Homogeneous mixtures with a dispersed phase in this size range may be called colloidal aerosols, colloidal emulsions, colloidal foams, colloidal dispersions, or hydrosols.
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