What is the meaning of the word "system"?

Definitions:

(physical chemistry) a sample of matter in which substances in different phases are in equilibrium noun
- In a static system oil cannot be replaced by water on a surface.
a complex of methods or rules governing behavior noun
- They have to operate under a system they oppose.
a group of independent but interrelated elements comprising a unified whole noun
- A vast system of production and distribution and consumption keep the country going.
a group of physiologically or anatomically related organs or parts noun
- Our body has a system of organs for digestion.
a procedure or process for obtaining an objective noun
- They had to devise a system that did not depend on cooperation.
instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity noun
- I bought a new stereo system.
the living body considered as made up of interdependent components forming a unified whole noun
- Exercise helped them get the alcohol out of their system.