Source. Crypto info.com
What is Stacks?
Stacks is a layer-1 blockchain solution that is designed to bring smart contracts and decentralized applications (DApps) to Bitcoin (BTC). These smart contracts are brought to Bitcoin without changing any of the features that make it so powerful — including its security and stability.
These DApps are open and modular, meaning developers can build on top of each other's apps to produce features that are simply not possible in a regular app. Since Stacks uses Bitcoin as a base layer, everything that happens on the network is settled on the most widely used arguably the most secure blockchain in operation — Bitcoin.