The word mind stems from the Indo-European '-men'. Just like men-tal , manas (Sanskrit) and 'hu-man' (Greek). Originally it means 'thinking and remembering'. The mind determines how we become aware of reality and how we experience it.
Our cognition (knowledge of the world) is both a way of viewing and perception itself. The mind receives what comes in through the senses, and starts with pattern recognition in relation to our memories. Thus, it is recognized and then a personal meaning is given dependent on our needs: what does it mean to me and what can/should I do with it?
The mind has various functions such as: "Selection, Analyzing, Recognizing, Constructing, Remembering Imagining, Imitating, Associating, Interpreting, and Organizing." In the brain, many things occur at the same time and eventuelly leads to an (imaginary) representation of reality. Then we react on that representation. The reality of the representation seems objective, but it is not.
What makes us human ?
What distinguishes us from other animals is the ability to mentalize. We learn language and play with concepts. We imagine things that do not yet exist. With that ability we can design and construct beautiful things such as a theory, a race car, a painting, a musical composition, or an image of the future. So the mind as an imaginary projector creates things that are not present in the direct reality.
An image of ourselves
Another thing we humans posess is self-awareness. That means: I am aware of an image of myself that differs from my peers. Some animals such as crows also have mental abilities (they use tools) and they have a kind of self-awareness because they recognize themselves in a mirror as being “this special bird” . The mind is a wonderful tool which is also used to “ mentalise ourself” and make an image of who I am and how I differ from other persons. Is that a good idea? Because everything the mind does is a imaginary representation, my selfimage will never fit into reality. So we might critisize the image, the ideas about ourself, but who is critisizing whom?
The mind as an illusionist
The mind is built in a way that make our imaginations seem completely real. How the illusionist works is obvious when we dream at night. But in the same way the mind works during the day. Half of the time we are busy with a kind of mental traveling. As it seem In the Middle Ages people were so busy with the devil that they felt his presence and saw him literally. That's exactly how our mind works. With everything we believe, the mind says: "At your service!". And it will presents reality in a way that confirms our faith and fears.
Mirroring other people
A part of our brain consist of mirror-neurons that imitate others and we experiences the actions of others as "real". If I see a mountain climber hanging on a wall I might feel (substitute) fear of height. If someone hits a hammer with a hammer, I can almost feel it myself. That compassion - experiencing emotions of others as our own - comes from the mirror neurons that make up 20% of our brain. Maybe thats why we love drama and reality series so much.
Body and mind
The two have a lot of influence on each other. For example: one minute in ice cold water and the physical system crashes. But with some people who practice (self)hypnosis or Yoga the heart rate stays calm, the temperature does not drop and they can spend several minutes in freezing water. There are many examples of the mind influencing the body like the placebo effect (yes I believe) and the necebo effect (no I do not believe) which have influence (+/- 30%) on healing processes. In case of trauma, the mind stays in a kind of "scaring condition" and can” t let go of old memory” s resulting in enduring psychological or fysiological pain.