a joint meeting, as of both houses of a bicameral legislature: The president addressed a joint session of Congress on the crisis in Central America.
Origin of joint session
An Americanism dating back to 1860–65
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for joint session
On the next day, I attended the joint-session of the two committees above named.Memoirs of Service Afloat, During the War Between the States|Raphael Semmes