basilica

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A public building of ancient Rome having a central nave with an apse at one or both ends and two side aisles formed by rows of columns, which was used as a courtroom or assembly hall.
• noun A Christian church building of a similar design, having a nave with a semicircular apse, two or four side aisles, a narthex, and a clerestory.
• noun Roman Catholic Church A church that has been accorded certain privileges by the pope.

from The Century Dictionary.

• A code of laws of the Byzantine empire, adapted from the laws of Justinian in the ninth century, by order of the emperor Basil I. Also Basilics.
• noun Originally, the stoa in which the king-archon dispensed justice in Athens; hence, in Greek antiquity, a frequent distinctive name for a stoa or portico.
• noun In Rome, where such buildings were introduced about, two centuries before Christ, a portico or hall recalling in plan or use the Athenian royal portico.
• noun Liturgically, in the Roman Catholic Church, a title conferred by the pope on a church without reference to its architectural arrangement, and carrying with it certain honors and privileges.
• noun In the middle ages, a name sometimes given to the elaborate structures raised over important tombs, as that over the tomb or shrine of Edward the Confessor in Westminster Abbey: so called, according to Ducange, because these structures bore a resemblance to diminutive churches.
• noun A large piece of ordnance: probably same as basilisk, 4.

from the GNU version of the Collaborative International Dictionary of English.

• noun Originally, the palace of a king; but afterward, an apartment provided in the houses of persons of importance, where assemblies were held for dispensing justice; and hence, any large hall used for this purpose.
• noun A building used by the Romans as a place of public meeting, with court rooms, etc., attached.
• noun A church building of the earlier centuries of Christianity, the plan of which was taken from the basilica of the Romans. The name is still applied to some churches by way of honorary distinction.
• noun A digest of the laws of Justinian, translated from the original Latin into Greek, by order of Basil I., in the ninth century.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun architecture A Christian church building having a nave with a semicircular apse, side aisles, a narthex and a clerestory.
• noun A Roman Catholic church or cathedral with basilican status.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a Roman building used for public administration
• noun an early Christian church designed like a Roman basilica; or a Roman Catholic church or cathedral accorded certain privileges