Is Starknet layer 2?

Could you please elaborate on whether Starknet qualifies as a layer 2 solution? I'm interested in understanding its position in the blockchain ecosystem and how it differs from other layer 2 protocols, if indeed it belongs to that category. Could you provide a concise yet comprehensive explanation of Starknet's characteristics and functionality, especially in comparison to traditional layer 2 technologies? I'm curious to know if Starknet offers unique advantages or solves specific challenges in the realm of scalability and decentralization. Thank you for your insights.