Colloid

Colloid a mixture of substances in which one is in the form of very small particles dispersed through the other. Examples are smoke (solid specks in air), foams (gas in a liquid), sols (solids in liquid, as in a mixture of starch and water), gels (sols that have ‘set’ by the solid particles linking into a network), and emulsions (one liquid dispersed in another). The substance which is split into particles is known as the disperse(d) phase; the other substance in which the first is dispersed is called the dispersion medium.