This is the 4538th most frequent Russian word.
выходным
"Выходным" means "weekend" or "day off" (in the instrumental case).
In this sentence, 'выходным' is used as a noun in its instrumental case form to indicate the relation to a day off.
Сегодня день перед выходным.
Today is the day before the day off.
Here, 'выходным' is an adjective describing Saturday, indicating its status as a day off.
Мой график работы делает субботу выходным.
My work schedule makes Saturday a day off.
'В выходным дне' uses 'выходным' as part of a prepositional phrase, showcasing the instrumental case to denote time or event context.