Autonomy can be defined as the part of you who gives, authors or creates your own law. This is what the Ancient Greek translation of the term suggests. It represents an important feature of the adult mind where the authority moves from out there, outside of you in the culture, leadership and experts whom presumably have more information and experience than you do to a fallible yet more trustable inner authority. Power shifts from outside of you to inside of you. When you begin to establish, author and create your own laws, ideologies and methodologies for directing yourself in the world, you are participating with autonomy.
This is a highly coveted ability for many adults as most can easily recall the pains of adolescence and early adulthood where an often unquestioned authority governed their actions in the world. Perhaps it was a teacher, coach, romantic partner or boss who, knowingly or unknowingly, governed your action and conduct in the world. When these are the only two basic reference points available, the only informed reasonable decision is to preserve inner directing autonomy at all costs.
