Sunday
noun
This is a day of the week. You know this because it has 曜日 in it. But what day of the week is it? The Sun day of the week is Sunday. Doesn't get much easier than that for you. Lucky!
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well. Just watch out for the ひ becoming a び like it did in the word 曜日.
来週の日曜日は予定があります。
I have plans for next Sunday.
日曜日の朝は、毎週教会に行きます。
I go to church every Sunday morning.
日曜日のハイキングで日焼けをしてしまいました。
I got injured during Sunday's hike.