The phrase "arena style" refers to an event or competition that takes place in a large enclosed space, typically in a circular or oval shape, where the audience can spectate from all angles. Full definition
Visual novel storyline, arena styled combat, what could go wrong? (cogconnected.com)
There are currently 2 maps featured in the Beta, and both are small - to - medium sized arena style maps that feature multiple level tiers and vantage points. (shortpause.com)
The brand new arena style shooter is fast and ruthless and forces you to sit back and learn a brand new game that is sure to shake up the genre. (gamingenthusiast.net)