A foreign stream is a schema object defined in the context of a SCHEMA, which is itself associated with a SERVER. Essentially, a foreign stream is an instance of a foreign data wrapper; which enables s-Server to access data flowing from or to an external system.
For example, the Extensible Common Data Adapter supports the creation of a foreign stream that reads data from the file system, network sockets, AMQP, Kafka, Kinesis, and so on.
For more information, see the section about the CREATE FOREIGN STREAM statement.