Autonomy is the ability to act, decide and govern oneself independently. From the individual sphere to social dynamics, autonomy appears as a common thread that guides our choices. Traditionally confined to human beings, the concept has expanded to include Artificial Intelligence (AI) systems. The same terminology is therefore used to designate two different types of autonomy. How can we define and differentiate between them? On the other hand, what brings them together and justifies the use of the same term? In this paper, we explore the essence of autonomy in Section 1 and its traditional philosophical definitions, as well as its applications in biomedical ethics. We call it natural autonomy. In Section 2, we define artificial autonomy by explaining what an autonomous system is, and by giving examples to illustrate our statement. Finally in Section 3, we compare these two forms of autonomy.