Rebekah Cook - Religious Practices

What makes a religious practice unique to its religion?  Is it the roots of the practice or the ritual involved?  Is it the specific clothes believers wear?  I think about this because one religious practice which has become so mainstream that most practice it without any religious intent – meditation.  It has so many different forms now but how did it get incorporated into so many religions?  While it is well-known that the Buddha is a very inspirational figure in the practice, some scholars claim that Jesus meditated as well.  Some question if Jesus event spent time in India.  If meditation is so sacred to one religion, how did it become accepted in another?  How did it become mainstream?