In chemistry, a suspension is a heterogeneous mixture of two or more substances. In a suspension, very small pieces of solid are spread through a liquid but do not dissolve.  If left still, the solid pieces will separate from the liquid and either fall to the bottom or rise to the top. Sand in water is a suspension. Suspensions may separate quickly or stay suspended for a long time, depending on what they contain.
- "Suspension". Merriam-Webster dictionary. http://mw1.merriam-webster.com/dictionary/suspension. Retrieved 2011-04-19.