Is Web3 an app?

Excuse me, but could you clarify something for me? I've been hearing a lot about Web3 lately, and I'm wondering if it's an app or something else entirely? Is Web3 a platform, a protocol, or a specific application that people can download and use? And if it's not an app, what exactly is it, and how does it differ from what we're used to with Web2 and traditional internet services? I'm really curious to understand the basics and how Web3 fits into the broader landscape of technology and finance.