1. (n.) The area in the central part of an amphitheater, in which the gladiators fought and other shows were exhibited; -- so called because it was covered with sand.

2. (n.) Any place of public contest or exertion; any sphere of action; as, the arena of debate; the arena of life.

3. (n.) Sand or gravel in the kidneys.

academic discipline academic specialty ambit amphitheater applied science area art assembly hall auditorium back backdrop background bailiwick beat border borderland chapel cincture circle circuit circus close concern concert hall confine container convention hall coop court courtyard curtilage dance hall delimited field demesne department department of knowledge discipline distance domain dominion enclave enclosure exhibition hall field field of inquiry field of study fold gallery ground hall hemisphere hinterland judicial circuit jurisdiction lecture hall list locale march meetinghouse mise-en-scene music hall natural science ology opera house orb orbit pale paling park pen precinct province pure science quad quadrangle realm rear ring round scene science setting social science specialty sphere square stadium stage stage set stage setting study technicology technics technology theater toft walk yard