Nominative plural (masculine), with same glossing in other lexica; evidently quoted from somewhere (perhaps Euripides, Alcestis 920).
The headword (which literally means 'well-fathered ones') can be either lower- or upper-case, i.e. used either generically or with application to the hereditary aristocracy of a particular city, usually Athens. For the Athenian Eupatridai see in brief John Davies in OCD(4) s.v.; more fully e.g. Robert Parker, Athenian Religion (1996) 60-65 and 323-324.