1. A group of interacting, interrelated, or interdependent elements forming a complex whole.
2. A functionally related group of elements, especially:a. The human body regarded as a functional physiological unit.
b. An organism as a whole, especially with regard to its vital processes or functions.
c. A group of physiologically or anatomically complementary organs or parts: the nervous system; the skeletal system.
d. A group of interacting mechanical or electrical components.
e. A network of structures and channels, as for communication, travel, or distribution.
f. A network of related computer software, hardware, and data transmission devices.

3. An organized set of interrelated ideas or principles.
4. A social, economic, or political organizational form.
5. A naturally occurring group of objects or phenomena: the solar system.
6. A set of objects or phenomena grouped together for classification or analysis.
7. A condition of harmonious, orderly interaction.
8. An organized and coordinated method; a procedure. See Synonyms at method.
9. The prevailing social order; the establishment. Used with the: You can't beat the system.

http://www.thefreedictionary.com/system