Английский словарь американских идиом - month of sundays

{n. phr.}, informal A very long time. - Used for emphasis after "for" or "in" and usually with a negative verb. * /I have not had devil's food cake in a month of Sundays./ * /When he got her first letter, he felt that he had not heard from her for a month of Sundays./ Syn.: DOG'S AGE.