Definition of a System
Consider what Edison wrote about his invention of a system of electric lighting, i love this phrasing and it is a perfect definition. It shows how inventors of those days spoke with words and not only formulas and numbers, it shows the literary artist inside every technical thinker:
"It was not only necessary that the lamps should give light and the dynamos generate current, but the lamps must be adapted to the current of the dynamos, and the dynamos must be constructed to give the character of current required by the lamps, and likewise all parts of the system must be constructed with reference to all other parts, since, in one sense, all the parts form one machine, and the connections between the parts being electrical instead of mechanical. Like any other machine the failure of one part to cooperate properly with the other part disorganizes the whole and renders it inoperative for the purpose intended." [source: Thomas Edison].