This is the 4009th most frequent Swedish word.
måndags
"Måndags" means "Monday's" (possessive form of Monday) in English.
In this sentence, 'måndags' is used to refer to the evening of a specific past Monday, acting adverbially in relation to the verb 'träffades' (met).
Vi träffades måndags kväll.
We met Monday evening.
Here, 'måndags' modifies 'morgon' (morning), indicating something characteristic or happening during a Monday morning.
Det var en frostig måndags morgon.
It was a frosty Monday morning.
In this case, 'måndags' is paired with 'förra' (last), expressing an occurrence specifically on the Monday of last week.