Final answer:
Adjourn sine die means to indefinitely suspend or end a legislative session without setting a date for reconvening, crucial in the context of legislative powers and proceedings.
Step-by-step explanation:
The term adjourn sine die refers to an indefinite suspension or end of a legislative session, meaning "without day." It implies that the legislative body, such as a Congress or parliament, has concluded its business and has no set date to reconvene. Concerning Congress, neither House can adjourn for more than three days without the consent of the other. This term is significant in the context of legislative proceedings, recess appointments, and the understanding of the separation of powers within the U.S. government.