There is some specialized terminology associated with BigchainDB. To get started, you should at least know the following:
A BigchainDB node is a machine (or logical machine) running BigchainDB Server and related software. Each node is controlled by one person or organization.
A set of BigchainDB nodes can connect to each other to form a BigchainDB network. Each node in the network runs the same software. A BigchainDB network may have additional machines to do things such as monitoring.
The people and organizations that run the nodes in a BigchainDB network belong to a BigchainDB consortium (i.e. another organization). A consortium must have some sort of governance structure to make decisions. If a BigchainDB network is run by a single company, then the "consortium" is just that company.
What's the Difference Between a BigchainDB Network and a Consortium?
A BigchaindB network is just a bunch of connected nodes. A consortium is an organization which has a BigchainDB network, and where each node in that network has a different operator.