土曜日と日曜日

The structure N1 と N2 forms a noun phrase equivalent to the English “N1 and N2”.

郵便局の休みは土曜日と日曜日です。
The post office is closed on Saturdays and Sundays.

Note: The particle と is not a drop-in replacement for the English word “and” as this usage only works when adding nouns. Verbs and adjective can also be added, but the method is different, as we will see later.