In plain English
An autonomous system uses sensors, data, and AI to operate and make decisions without a human directing each action. Autonomy is a spectrum: a system might handle routine conditions itself while still handing difficult cases back to a person. The degree of independence, and what happens when the system is unsure, are the questions that matter most for safety.
Why it matters
The more independently a system acts, the more important it is to define who is accountable for its decisions and how a human can intervene when something goes wrong.
A worked example
A warehouse robot that navigates aisles, avoids obstacles, and picks items without step-by-step instructions is operating autonomously within its defined area.
Common confusion
Autonomous does not mean infallible or unsupervised. Well-designed autonomous systems still include limits, monitoring, and a way for people to take back control.