a baldachin is a ceremonial canopy of stone, metal, or fabric over an alter, throne or doorway.
A baldachin, or baldaquin, is a canopy of state over an altar or throne. It had its beginnings as a cloth canopy, but in other cases it is a sturdy, permanent architectural feature, particularly over high altars in cathedrals, where such a structure is more correctly called a ciborium when it is sufficiently architectural in form.
