What is it called when Congress calls for a special session?

A special session of Congress occurs when the President calls Congress back into session after it has adjourned for a recess. This is typically done to address urgent matters that arise between the regular sessions of Congress. The term "special session" reflects this purpose, distinguishing it from regular sessions that take place at set times throughout the year.

In contrast to other terms that might suggest gatherings of Congress—like "joint session" which includes members from both the House and Senate meeting together, or "extraordinary meeting" which isn't a formal term used in the legislative context—"special session" is the official designation recognized by law. Similarly, "emergency session" may imply urgent circumstances but is not the standard term for this specific scenario. Thus, the definition of a special session aligns with the procedural actions of Congress to convene outside of its regular schedule, making it the correct answer.