What is "déjà vu"?

Have you ever felt that you as if ever do or through the moment?
it called "déjà vu" come from france language means that "already seen"
Some theori say that actually come from the same phenomenon that we've ever done by our soul in once upon a time in the past.
the experience of déjà vu seems to be quite common among adults and children alike.
As much as 70 percent of the population reports having experienced some form of deja vu. A higher number of incidents occurs in people 15 to 25 years old than in any other age group.
Another theory being explored is that of vision. As the theory suggests, one eye may record what is seen fractionally faster than the other, creating that "strong recollection" sensation upon the "same" scene being viewed milliseconds later by the opposite eye. However, this one fails to explain the phenomenon when other sensory inputs are involved, such as the auditive part, and especially the digital part. If one, for instance, experiences déjà vu of someone slapping the fingers on his left hand, then the déjà vu feeling is certainly not due to his right hand experiencing the same sensation later than his left hand considering that his right hand would never receive the same sensory input. Also, persons with only one eye still report experiencing déjà vu or déjà vécu (a rare disorder of memory, similar to persistent déjà vu). The global phenomenon must therefore be narrowed down to the brain itself (say, one hemisphere would be late compared to the other one).
Do you know,, that not only people who can see who ever feel it,but people who cannot see also can feel it by their nose, ear, and by their skin.