
Psychic is a term relating to or denoting mental abilities or phenomena that are apparently inexplicable by known natural laws, since they seem to transcend the confines of the brain. People who are thought to have these abilities or to be able to produce these phenomena are often called "psychics". The term comes from the Greek word psychikos, meaning "of the soul, mental," which is in turn derived from the Greek word psyche (soul/mind). It was first used by French astronomer Camille Flammarion (1842 - 1925), who was also a noted spiritualist and psychical researcher.
Everyone has the opportunity to develop some degree of psychic ability. As we are all spiritual beings existing on a physical plane, communication between spirits would not be limited to the spoken word... to voice. We always have been and always will be spirit, so our mind must have the ability to communicate with others on a spiritual level.

So what is a psychic? Not as simple a question to answer as I first thought
It would appear we are all psychic to a certain degree but our open mindedness, awareness and of course development would all be factors that could determine our level of ability.
The most culturally acceptable definition of someone who is psychic would be one who knows how to read and translate information received that would be coming from another person in order to help that person in their life. Using senses not confined to the usual 5 physical senses of sight, hearing, smell, touch and taste.
To understand the science of psychic ability is not as simple a task as I first thought. As there is no common thread or path to becoming a psychic, it is difficult to map out even basic characteristics of people who have become psychic. Self-awareness, personal development and life-experience would all be factors that could determine one's ability. It also seems there are broad factors to consider such as society's acceptance of paranormal activity and evolution of collective consciousness. So it seems there would be two types of connection,
A mind to mind and a mind to collective mind.
Our aura or spiritual being, through an act of mind, acts much like a radio transmitter, sending and receiving signals. The individual, through study, meditation, or personal growth seems to gain the ability to transmit and receive higher frequencies that are typically not discernable to the common man. This attunement to frequencies beyond base human experience may be a connection to the source energy of all matter in the universe. This source energy can act as an information highway to the psychic.
Psychics sometimes use a tool as a means of focus. Tools can be literally anything but there are some things that are more accepted to serve this purpose. Some of the well known psychic tools would be Tarot, Runes and Crystals.
Delving deeper into the difference between being a psychic and a medium requires further understanding of "connections" and what we are connecting to.
It is scientific fact that we are all connected at a quantum level. Metaphysics tells us that all matter in the universe is at its subatomic level, vibrating strings of energy. Vibrating energy that has properties. High and low, dense and light, expansive and contractive. As all matter is energy, it must contain information in order to give it form. Human form as well. Understanding this energy, tapping into this intelligence, allowing of its knowledge is the art and craft of the psychic.
"Many impressively credentialed top-grade scientists are independently making discoveries in areas such as homoeopathy, bio-electrography, remote viewing and healing through prayer. These are all areas that challenge traditional reductionist scientific thinking. Their findings support the new view of a world in which everything is interconnected in a pulsating energy field (McTaggart 2001)."
There is something called the Zero Point Energy field, this was at one time considered to be the vacuum or nothingness of space but recently scientists have discovered that in actual fact it isn't nothing at all. The Field is a subatomic field of unimaginably large quantum energy in so-called empty space. If you add up all the movement of all the particles of all varieties in the universe, you come up with a vast inexhaustible energy source all sitting there unobtrusively in the background of the empty space around us, like one all-pervasive, supercharged backdrop. To give you some idea of the magnitude of that power, the energy in a single cubic yard of 'empty' space is enough to boil all the oceans of the world.
Perhaps more important, the existence of the Zero Point Field implies that all matter in the universe is interconnected by quantum waves, which are spread out through time and space, and can carry on to infinity, tying one part of the universe to every other part. The idea of The Field might just offer a scientific explanation for the spiritual beliefs of many religions that there is such a thing as a life force.
The Zero Point Field may provide a scientific explanation for many of the most profound human mysteries, including many phenomena that we have not been able to provide an adequate explanation for. Ordinarily, the capacity of our brains to receive information from this energy field is strictly limited - like a radio with only a certain limited bandwidth. During ESP and remote viewing or clairvoyance - the ability to 'see' things beyond ordinary distances - it appears that this bandwidth expands, giving us more access to information in the Field than we would have ordinarily.
So it seems that psychic abilities would infact be something that we can all do if we literally open our minds to receiving information that is beyond the limits of this material world and the boundaries science has laid out for us.
Science hasn't been able to work out many of the details of psychic abilities but progress has been made as at least it is recognized as existing, and looks like were beginning to understand the process.
If the emerging world picture is to be completed, we must evolve an explicit hypothesis to describe the basic dynamics of the overall range of matter-vacuum interaction. In this writer's "quantum- vacuum interaction (QVI) hypothesis," the non- classical energy field of the vacuum (consisting of scalar as well as electromagnetic wave propagations) registers the spacetime behavior and evolution of matter- energy systems in the form of interfering wavefronts. The conserved interference patterns form a holographic information field accessible to systems with a stereodynamic pattern isomorphic to the systems that produced the patterns. The applicable process can be described as forward and reverse Fourier (more exactly, Gabor) transforms. Hence matter- energy systems ranging from quanta to complex atomic, molecular, cellular and multicellular structures, including human brains, decode ("read out") the information they and analogous systems have encoded ("read into") the field. Given that wavefronts superpose in multiple dimensions, the ZPF of the vacuum acts as an information- conserving and transmitting universal holofield, intercon- necting systems with each other, as well as with their subsidiary systems (internal parts) and suprasystems (external environments)
The mind is not a closed system or a finite place or space... but rather acts as a "gateway". It functions as the gateway between the conscious and the sub- conscious; it operates as a bridge between physical and non-physical systems. It is almost certain that we probably live in a multidimensional universe where there are multiple layers of existence to explore. There are multiple theories that state this, which would include the String Theory, Superstring theory and the M theory.
Consciousness of the mind is pure energy and energy never dies; conscious thought simply remains with the spiritual body, once the physical body dies. That energy might change... it can continue to grow... it may evolve into something greater than itself, but it never fades away into nothingness......
What is a medium?
A medium is somebody who acts as a mediator between the spirit world and the earth plane. I found this in the dictionary..
"A person thought to have the power to communicate with the spirits of the dead or with agents of another world or dimension. Also called psychic"
I thought that was a little vague so looked up mediumship in Wilkepedia which states ..
Mediumship is a term used mostly in spiritualism to denote the ability to produce psi phenomena of a mental or physical nature. According to spiritualists, mediumship often involves communication between a human instrument and one or more discarnate, spirit personalities. Spiritualists refer to such a human instrument as a medium.
There are two mains types of Mediumship, the first being Mental Mediumship which is communication, via the varied aspects of thought transference, or telepathy. Mental mediumship takes place within the consciousness of the medium.
The second type of mediumship is called Physical mediumship. Physical mediumship involves the manipulation and transformation of physical systems and energies. The spirit operators, in this case, are said to be causing something to happen upon the Earth plane. What it is that actually happens varies with the style of mediumship involved, but the results can be seen and heard by others.
So what is the difference between a psychic and a medium??
Mediumship is different for one main reason which is that as a medium you need to create a connection with the Spirit World, you have to shift your focus and alter your state of consciousness somewhat, to a higher level or tune into a higher frequency. We are then connecting with a spirit mind in the same way we would in a psychic link.
The messages from a psychic and a medium are different also, Mediums provide evidence of survival and would describe the spirit that they are communicating with and some evidence that the sitter would connect with this person. Most importantly a message from the spirit person will be delivered to the person receiving the reading.
A psychic in my opinion is giving the sitter another perspective upon which to look at their life in the hope that they can help themselves obtain the best possible outcome for the future.
"Now your world has seen the havoc wrought and the benefits that can be obtained by nuclear fission. The basis of materialism has been split altogether: the indissoluble atom has been dissolved. Scientists accept that matter is not solid, and that reality is to be found in the invisible."
Silver Birch, "Light from Silver Birch" (1983)
References
Johanne Beacall, 10 June 2007
The Spiritual Universe, Fred Alan Wolf
The Field: The quest for the secret force of the Universe, Lynne McTaggart
Subtle Connections: Psi, Grof, Jung and the Quantum Vacuum , Ervin Laszlo. cf. Ervin Laszlo, The Creative Cosmos.. Floris Books, Edinburgh, 1993
Lodge, Sir Oliver, "Ether and Reality" 1925 (Hodder & Stoughton)
The Scientific Proof of Survival after Death By Michael Roll