When the Parthenon was built between 447BC and 432BC, three sets of sculptures, the metopes, the frieze and the pediments, were created to adorn it. Of these, the metopes and the frieze were part of the structure of the Parthenon itself. They were not carved first and then put in place, high up on the Parthenon, but were carved on the sides of the Parthenon itself after it had been constructed.
Thus, the Marbles as a whole were part of the Parthenon and not individual sculptures. Furthermore, “Parthenon Marbles” term has a broad and strong connotation, which goes back to when Melina Mercury started the “epanapatrismo twn marmarwn”. Even though some newer terminology has started calling them the “Parthenon Sculptures”, this term suggests more to individual pieces of art. The “Parthenon Marbles” term convey a strong meaning that the Marbles as a whole were “part of” the Parthenon structure.
In addition, the intent for this projects is not only for the reunification of the British Museum items, but also for other parts located in Paris, Vienna, Munich, and Copenhagen.