the day, week, etc. just before the most recent one; two days, weeks, etc. ago :
I haven't seen him since the summer before last.
the day, week, etc. just before the most recent one; two days, weeks, etc. ago :
I haven't seen him since the summer before last.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005