Real Dictionary

Elgin marbles in American English
a collection of ancient Athenian marble sculptures taken chiefly from the Parthenon, in the British Museum since 1816
plural noun: a group of Greek sculptures of the 5th century b.c., originally on the Parthenon in Athens, and supposedly sculptured under the direction of Phidias: presently in the British Museum in London

Elgin marbles in British English
plural noun: a group of 5th-century bc Greek sculptures originally decorating the Parthenon in Athens, brought to England by Thomas Bruce, seventh Earl of Elgin (1766–1841), and now at the British Museum