Cosmos is a decentralized network of independent blockchains. Instead of connecting each blockchain with other individually (connections would grow exponentially with an increasing number of blockchains), Cosmos runs a modular architecture with two classes of blockchain: “Hubs” and “Zones”.
Zones are regular blockchains built by users for specific use cases and Hubs are designed to connect Zones together. When a Zone creates a connection with a Hub, it can automatically access (i.e. send to and receive from) every other Zone that is connected to it. Therefore, each Zone only needs to establish a limited number of connections with a restricted set of Hubs.
The first Hub launched in the Cosmos network is the Cosmos Hub. The Atom token underpins the Cosmos network and is used to both secure the network through staking and vote on governance decisions.
Cosmos advertises itself as the internet of blockchains, a network of blockchains able to communicate with each other in a decentralized way.