Acropolis
2 of the 7 encyclopedias on this shelf carry an entry for Acropolis. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a-krop'o-lis, a Greek word signifying the high part of a city, the portion set on a hill. The name grew out of the fact that Greek cities were founded usually on an eminence which was fortified as a citadel. As the city grew, it spread to the lower grounds and was not infrequently surrounded by a strong wall; while the acropolis was made the site of the temple and other public buildings. This was the case of Argos, Thebes, and Corinth. The most noted acropolis is that of Athens. The acropolis of Athens is a table of rock about 260 feet high. It is a spur of Mt. Hymettus with precipitous sides except on the west, where a zigzag road was built, accessible by chariots. The summit was surrounded by massive walls. A number of notable buildings were erected here, the best of which were two temples, the Parthenon and the Erechtheum. The famous open air theaters of Athens were constructed on the sides of this acropolis. See Athens ; Pericles ; Parthenon Into the center of the entire plain advances from the direction of Hymettus a group of rocky heights, among them an entirely separate and mighty block which, with the exception of a narrow access from the west, offers on all sides vertically precipitous walls, surmounted by a broad level sufficiently roomy to afford space for the sanctuaries of the national gods and the habitations of the national rulers. It seems as if nature had designedly placed this rock in this position as the ruling castle and the center of the national history. This is the Acropolis of Athens.--E. Curtius, History of Greece. Acropolis Restored. Acropolis
Collier's New Encyclopedia (1921)
the high part of any ancient Greek city, usually an eminence overlooking the city, and frequently its citadel. Notable among such citadels were the Acropolis of Argos, that of Messene, of Thebes, and of Corinth, but pre-emi- 7nently the Acropolis of Athens, to which the name is now chiefly applied. The Acropolis of Athens was the original city of Athens, later the upper city, as distinguished from the lower, and was built upon a separate spur or butte of Hymettus. The hill rises out of the plain, a mass of rock about 260 feet high. The summit of this rock forms an uneven plain 500 by 1,150 feet at the maximum breadth and length. Within this area were reared, chiefly in the days of Pericles, remarkable specimens of architectural art. The buildings were grouped around two principal temples, the Parthenon and the Erechtheum. Between these temples stood the statue of Athena Promachos (fighter in front), by Phidias, the helmet and spear of which were the first objects visible from the sea. About these center pieces were lesser temples, statues, theaters, fanes, and odea (mubuildings sic halls). Among the famous on the sides of the Acropolis were the Dionysiac theater and the Odeum of Pericles, and the Odeum, built by Herodes Atticus in honor of his wife, Regilla. The ravages of accident and war and Athenian marble-merchants have largely destroyed and despoiled these classic works. See ATHENS.