The word "arena" comes from the Latin word "harena", which means "sand". In ancient Rome, arenas were large, oval-shaped amphitheatres that were used for gladiatorial contests and other public spectacles. The arenas were covered in sand, which helped to absorb the blood of the gladiators and animals that were killed in the contests.
The word "arena" is still used today to refer to a large, open space that is used for public events, such as sports matches or concerts. The word can also be used figuratively to refer to a place of competition or conflict.