circus

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

• noun A public entertainment consisting typically of a variety of performances by acrobats, clowns, and trained animals.
• noun A traveling company that performs such entertainments.
• noun A circular arena, surrounded by tiers of seats and often covered by a tent, in which such shows are performed.
• noun A roofless oval enclosure surrounded by tiers of seats that was used in antiquity for public spectacles.
• noun Chiefly British An open circular place where several streets intersect.
• noun Informal Something suggestive of a circus, as in frenetic activity or noisy disorder.

from The Century Dictionary.

• noun In Roman antiquity, a large, oblong, roofless inclosure, used especially for horse- and chariot-races.
• noun In modern times, a place of amusement where feats of horsemanship and acrobatic displays form the principal entertainment; the company of performers in such a place, with their equipage; the entertainment given.
• noun In England, the space formed at the intersection of two streets by making the buildings at the angles concave, so as to give the intervening space the form of a circle: as, Oxford Circus, Regent Circus, in London.
• noun An inclosed space of any kind; a circuit.
• noun [capitalized] In ornithology, a genus of diurnal birds of prey, the harriers, typical of the subfamily Circinæ (which see)

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

• noun (Roman Antiq.) A level oblong space surrounded on three sides by seats of wood, earth, or stone, rising in tiers one above another, and divided lengthwise through the middle by a barrier around which the track or course was laid out. It was used for chariot races, games, and public shows.
• noun A circular inclosure for the exhibition of feats of horsemanship, acrobatic displays, etc. Also, the company of performers, with their equipage.
• noun rare Circuit; space; inclosure.

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

• noun A traveling company of performers that may include acrobats, clowns, trained animals, and other novelty acts, that gives shows usually in a circular tent.
• noun A round open space in a town or city where multiple streets meet.
• noun historical In the ancient Roman Empire, a building for chariot racing.
• noun military, World War II A code name for bomber attacks with fighter escorts in the day time. The attacks were against short-range targets with the intention of occupying enemy fighters and keeping their fighter units in the area concerned.
• noun obsolete Circuit; space; enclosure.

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

• noun an arena consisting of an oval or circular area enclosed by tiers of seats and usually covered by a tent
• noun a genus of haws comprising the harriers
• noun a travelling company of entertainers; including trained animals
• noun a frenetic disorganized (and often comic) disturbance suggestive of a large public entertainment
• noun (antiquity) an open-air stadium for chariot races and gladiatorial games
• noun a performance given by a traveling company of acrobats, clowns, and trained animals