Fedimint is a modular, open-source protocol to custody and transact bitcoin and more in a community context, built on a strong foundation of privacy. This includes a base set of modules, among them including: federated consensus, bitcoin multi-signature, Chaumian eCash, Lightning Network integration, and Bitcoin transactions.

You can also speak of a fedimint, or multiple fedimints, which are application server instances of the Fedimint protocol.

If you want to learn more about Fedimint access https://fedimint.org/