numerosity (n[y]oo-m<<schwa>>r-ahs-<<schwa>>-tee). The requirement that, for a case to be certified as a class action, the party applying for certification must show, among other things, that the class of potential plaintiffs is so large that the joinder of all of them into the suit is impracticable. See CLASS ACTION. [Cases: Federal Civil Procedure 163.]

[Blacks Law 8th]