It is interesting that a clinical professor of psychiatry at the UCLA School of Medicine had asked over time a hundred thousand other mental health professionals such as psychiatrists, psychologists, nurses, social worker etc from all over the world if they have attended a lecture where they have been given a definition of the mind. Surprisingly he found out that only a low 2 to 5% responded yes. He had gathered a group of 40 scientists from a wide range of fields and came out with a definition of the mind that all could agree upon which states, "The human mind is a relational and embodied process that regulates the flow of energy and information." Now this is something so modern and abstract sounding but still has good logical sense that everyone could be united to agree and accept it. You can hear his talk at Google Tech Talks on video here.
Throughout history, there has been differing opinions and philosophies about what the mind is or whether it has unity or is separated from the body etc. I wasn't caught in the complexity of various opinions of philosophers or scientists as from young I took the simple path of turning to my own observations which came from a 'turning of the camera' on to myself as well as to others and making notes during my life time. This was simply a natural process for me of thinking about my own thinking as I observed myself which has a term known as Critical thinking that generally refers to high-order thinking that questions assumptions.
To me, the mind is the central processing unit of our human system just as the CPU is in a computer system. I appreciate my mind like how I appreciate the computer. I don't have to understand totally how it works inside! My approach is to treat the Mind as a black box where much can already be learnt by observing the inputs to the mind and how it relates to the output. From such personal observations, I began forming many of my own hypothesis or theories about the human mind, not just of my own mind but of others too that I have had the privilege to associate with over my lifetime. This I have done through active engagement in networks of the family, business and several non-profit social organizations. I get a kick later in life by the readings, as part of the research I started, on what the scientists and professors have to say from their scientific discoveries as I find there is close correlation of these discoveries with my own discoveries from experiences and experiments of my life time.