Thanks to the fact that the citizens of ancient Rome liked to see gory contests, gladiators fighting one another to the death, starved wild animals turned loose upon human victims, the ground of the amphitheaters was always liberally covered with sand to soak up spilled blood.
And the Latin word for sand is arena.
Nowadays an “arena” may never know blood, it may never see sand; it merely denotes a scene of contest, physical, mental, or even figurative.
