Festival Day, National Holiday
noun, の adjective
A festival day is obviously a festival day. This word technically refers to days for Shinto festivals or rituals, but sometimes people also use it to mean a general national holiday. This is because some of the Japanese national holidays are based on those traditional Shinto festival days!
さいじつ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
今日は祭日だからいつものカフェがお休みだったよ。
Today is a national holiday, so the coffee shop I usually go to was closed.
祭日なのに、仕事なの？
Do you have to work even though it's a national holiday?
祭日だってことを忘れていて、会社に来てしまった。
I forgot it was a holiday and I came to the office.