What does 'mass tort' mean?

These are civil actions that have a 'mass' of plaintiffs against one or more defendant corporations, giving rise to 'mass tort litigation.'

Mass Tort litigations generally play out in one of two procedural formats: (1) Class Action = the court finds that the questions of law or facts common to class members predominate over any questions affecting only individual members, and (2) Multidistrict Litigation = when civil actions involving one or more common questions of fact are pending in different districts, such actions may be transferred to any district for coordinated or consolidated pretrial proceedings.