Homeostasis is the term used to describe a cells ability to maintain a stable internal environment. Coined in 1959, the term refers to the chemical and physical parameters that any organism or cell needs to maintain in order for it to function properly.
There are differences between the manner in which a single cell maintains its homeostasis and how a much more complex multicellular organism accomplishes it. The single-cell organism can, for instance, simply dump its waste products outside its cell wall. A multicellular organism (such as a dog, cat or human) needs to have its wastes taken away by various organ systems in order to remove these potentially toxic materials to a safe place outside the body.