This is the 504th most frequent Swedish word.
lördag
Saturday.
Here, 'lördag' is used as a temporal noun denoting the specific day (Saturday) when an event is planned.
På lördag ska vi gå på bio.
On Saturday, we will go to the cinema.
In this sentence, 'lördagar' is plural, indicating a recurring aspect referring to all Saturdays generally.
Lördagar är vanligtvis en ledig dag.
Saturdays are usually a day off.
'lördag' specifies the actual occurrence of an event within a specific week in this context.