Broker-dealer
A foreign broker-dealer (foreign being from the perspective of the United States of America), means that poor, huddled mass of international broker-dealers who were turned away, or never arrived, at Ellis Island and have not subsequently been registered with the Securities and Exchange Commission, whereas a registered broker-dealer denotes one of those blessed souls who have.
Of much interest to those wanting to handle or "effect" transactions in securities with US persons. The SEC has lots of rules about this, and as you can probably imagine they're entirely simple, clear and easy to formulate.