A public meeting of persons in mass, or of all classes, to consider or listen to the discussion of some matter of common interest.(noun)
The Century Dictionary (Public Domain)
Use "mass-meeting" in a sentence
"In his email to members, Woodley said a ballot for industrial action remained a possibility, with Bassa due to hold a mass-meeting next week to gather members 'opinions on the next move."
"We ought to organize a great central mass-meeting for the Sunday night before the Monday when the bill comes up for final hearing."
"In introducing Carl Schurz at a great mugwump mass-meeting at"