ereyesterday UK /ɛəˈjɛstədeɪ/US /ɛəɹˈjɛstəɹdeɪ/adverb 1noun 1 adverb1 •(Scotland) On the day before yesterday.Friday last (ere yesterday) Cardinal Mazarine came to receive and confer vvith her upon all the demands, motions, and articles she vvould propound; […] — 1644 noun1 •(Scotland) The day before yesterday.And Iacob behelde Labans countenaunce, ⁊ beholde, it was not towarde him as yesterdaye and yeryesterdaye. — 1535