n. 角斗场；竞技场（arena的复数形式）

Arena \A*re"na\, n.; pl. E. {Arenas}; L. {Aren[ae]}. [L. arena,
harena, sand, a sandy place.]
1. (Rom. Antiq.) 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. Any place of public contest or exertion; any sphere of
action; as, the arenaof debate; the arena of life.

3. (Med.) ``Sand'' or ``gravel'' in the kidneys.