A lot vs. Alot: 9 Grammatical Pitfalls
plural of ruga (1775), from Latin ruga "a wrinkle in the face," from PIE *rug-, variant of *reue- (see rough (adj.)).
ruga ru·ga (rōō'gə)n. pl. ru·gae (-gē', -gī') A fold, crease, or wrinkle, as in the lining of the stomach. Often used in the plural.