noun
Basic unit of time; also used for counting days.
一日は二十四時間です。
A day is 24 hours.
あと三日で夏休みが終わる。
Summer vacation ends in three more days.
noun
The sun itself or its light/rays.
日が沈む。
The sun sets.
この部屋は日がよく当たる。
This room gets a lot of sunlight.
noun
The period of daylight, as opposed to night.
日が長くなった。
The days have gotten longer.
日のあるうちに帰ろう。
Let's go home while it's still daylight.
noun
A specific day on the calendar; often used for deadlines or scheduled days.
提出の日は来週の金曜日です。
The submission date is next Friday.
約束の日を忘れないで。
Don't forget the day of our appointment.
noun
past days; time (of one's childhood, etc.)
Refers to a period in the past, often with nostalgic or reflective nuance.
学生時代の日々が懐かしい。
I miss the days of my student life.
あの日にはもう戻れない。
We can't go back to those days.
noun
case (esp. unfortunate); event
Used in set patterns like 〜した日には or 〜と来た日には to mean 'when it comes to...' or 'in the event of...', often implying an undesirable situation.
彼が怒った日には、誰も近づけない。
When he gets angry, nobody can go near him.
雨が降った日には、試合は中止だ。
In the event of rain, the game will be canceled.
太陽 is the astronomical term for 'sun', while 日 is the everyday word for the sun as seen in daily life.
昼 means 'noon' or 'daytime' as a time of day, while 日 can refer to the entire daylight period or a calendar day.
日付 specifically means 'date' in a formal or written sense, while 日 is a more general word for a day or date.
Native Japanese word. The kanji 日 is a pictograph of the sun and is used for both 'sun' and 'day' meanings across East Asian languages.