noun

1. in ancient Rome, an oval or oblong arena with tiers of seats around it, used as for games or chariot races
2. a similar arena, often enclosed in a tent or building for performances by acrobats, trained animals, clowns, etc.
3. a traveling show of this sort or its personnel, equipment, etc.
4. the performance of such a show
5. Brit. a circular open place where many streets come together: used esp. in place names
6. ☆ Informal anything thought of as being like a circus, as an event, place, or activity that is riotously entertaining, spectacular, frenzied, disorganized, etc. a media circus

Etymology: L, a circle, ring, racecourse < or akin to Gr kirkos, a circle < IE *kirk- < base *(s)ker-, to turn, bend > Gr korōnos & L curvus, curved