The 'ESP' in psychic ESP stands for extra-sensory perception.
We have five traditional bodily senses, and therefore five ways of sensory perception: hearing, touch, smell, taste and sight. ESP means perception that comes from beyond our bodily senses.
We can say that there are two basic views about what actually constitutes ESP: the 'non psychic ESP' view and the 'psychic ESP' view.
The 'non psychic ESP' view correctly recognizes that it is not our ears or eyes where perception truly occurs, but in our brain. This is where useless data is converted into useful information, and perception as we experience it occurs mostly within our brains. According to the non psychic ESP view, our brains are the biological source of ESP.
The 'psychic ESP' view recognizes that on the deepest level our human selves are one with the universe; our consciousness is the consciousness of the universe. We are capable of psychic ESP because we are one with the things we perceive.
Both the 'non psychic ESP' and the 'psychic ESP' views are important to psychic development.