What is THORChain RUNE?

Excuse me, could you please elaborate on what THORChain RUNE actually is? I've heard quite a bit about it in the crypto circles, but I'm still a bit hazy on the specifics. Is it a type of cryptocurrency? Or perhaps a platform for decentralized finance? Could you break down its functionality and significance in the broader crypto ecosystem? I'm eager to understand its role in the world of finance and how it might impact the future of blockchain technology.