noun

1. A machine or robot designed to follow a precise sequence of instructions.

2. A person who acts like a machine or robot, often defined as having a monotonous lifestyle and lacking in emotion.

   "Due to her strict adherence to her daily schedule, Jessica was becoming more and more convinced that she was an automaton."

3. A formal system, such as finite automaton.

4. A toy in the form of a mechanical figure.

5. The self-acting power of the muscular and nervous systems, by which movement is effected without intelligent determination.