a legal action (= a case that is decided in a law court) that is organized by a group of people who all have the same legal problem

Plaintiffs' lawyers have tried to get the courts to combine all the potential suits into a single class action. 原告律师试图让法庭将所有潜在的诉讼放在一起，成为一个集体诉讼。

[ before noun ] a class-action lawsuit 一桩集体诉讼案