Final answer:
The term for a railing enclosing a sacred area like a stupa is 'Vedika', which is part of Buddhist architectural traditions and can be seen at the Mahabodhi Temple.
Step-by-step explanation:
The railing enclosing a sacred area, such as a stupa, is known as a Vedika. In the context of Buddhist architecture, this term refers to the stone fence that surrounds a stupa.
An example of this can be seen at the Mahabodhi Temple, where the railings around the temple have sandstone posts dating back to 150 BCE, with most erected during the Gupta period with embellishments that include figures and stupas. These types of railings are characteristic of classical Indian temples and are integral to the structure and the aesthetics of the sacred space they define.