This is the 638th most frequent Swedish word.
fredag
Friday.
Here, 'fredag' refers to a specific day of the week when a planned event occurs in the future.
Vi träffas på fredag för att fira tillsammans.
We meet on Friday to celebrate together.
In this case, 'fredagar' refers to Fridays in a general sense, as a recurring time period.
Fredagar är mina favoritdagar på veckan.
Fridays are my favorite days of the week.
Here, 'i fredags' specifies the past Friday, indicating a particular instance of the day.