This is a concept that is central to cryptocurrency. A system of sharing information between individuals on a network rather than going through a central authority. In the case of Bitcoin, the network is built in such a way that each user is broadcasting the transactions to other users. No bank is required as a third party.
Malone, J.A (2015). Glossary of Bitcoin Terms and Definitions. United States: Lulu Press, Inc
A network of computers that are collectively able to perform functionalities normally only possible with centralized, server-based services.