a month of Sundays

US /ə mʌnθ əv ˈsʌn.deɪz/
UK /ə mʌnθ əv ˈsʌn.deɪz/
"a month of Sundays" picture
1.

a very long period of time

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I haven't seen him in a month of Sundays.
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It will be a month of Sundays before they finish that project.
:
sundaymonthSunday bestflavour of the month