Is Arbitrum one an ERC20?

Excuse me, could you clarify something for me? I've been reading about Arbitrum and I'm a bit confused. I understand that it's a scaling solution for Ethereum, but I'm wondering if Arbitrum itself is an ERC20 token? Or is it something entirely different? I'm trying to get a better grasp on the differences between Arbitrum and ERC20 tokens, and how they fit into the broader Ethereum ecosystem. Could you help me understand this?