Is gnosis an Ethereum?

Could you please clarify for me if Gnosis is indeed an Ethereum-based project? I've heard some rumors that it's closely tied to the Ethereum blockchain, but I'm not entirely sure. Could you explain how Gnosis interacts with Ethereum, if it does indeed operate on its platform? Also, is Gnosis considered a decentralized application, or does it have a more centralized structure? I'm curious to understand the nature of its relationship with Ethereum and how it fits into the larger cryptocurrency and finance ecosystem.