一日(いちにち)

いちにち
noun
one day, all day
time-general
1. one day (duration)
A period of 24 hours or one full day.
一日(いちにち)に何(なん)時間(じかん)働(はたら)きますか。
How many hours do you work in one day?
東京(とうきょう)で一日(いちにち)過(す)ごしました。
I spent one day in Tokyo.
旅行(りょこう)は一日(いちにち)で終(お)わります。
The trip will end in one day.
この仕事(しごと)は一日(いちにち)では終(お)わりません。三日(みっか)ぐらいかかります。
This work won't be done in one day. It takes about three days.
一日(いちにち)で終(お)わると思(おも)いましたが、二日(ふつか)かかりました。
I thought it would be done in one day, but it took two days.
2. all day, the whole day
Throughout an entire day from morning to night.
一日(いちにち)中(じゅう)雨(あめ)でした。
It rained all day.
一日中 = all day long
一日(いちにち)中(じゅう)本(ほん)を読(よ)んでいました。
I was reading books all day long.
日曜日(にちようび)は一日(いちにち)家(いえ)にいました。
I stayed at home all day on Sunday.
子供(こども)たちは一日(いちにち)中(じゅう)外(そと)で遊(あそ)んでいました。
The children were playing outside all day long.
風邪(かぜ)を引(ひ)いたので、一日(いちにち)中(じゅう)寝(ね)ていました。
I caught a cold, so I was sleeping all day.
一日(いちにち)ゆっくり休(やす)んでください。
Please rest for the whole day.

一日(いちにち) refers to a period of one day or, with 中(じゅう), means 'all day long.'

Pronunciation

When meaning 'the first day of the month,' this word is read 一日(ついたち), not いちにち.

Common patterns

Duration counting

For counting days as a duration, Japanese uses the native number system:

The suffix 間(かん) is optional for 一日(いちにち) but typically added for other counts (二日間(ふつかかん), 三日間(みっかかん)).

Related Words

Compare: 一日(ついたち) (same kanji, read ついたち (1st of the month))
Related: 一日中(いちにちじゅう) (all day long)
Compare: 一昼夜(いっちゅうや) (a whole day and night)
Compare: 半日(はんにち) (half a day)
basic
Added 2026.1.7 21:40 · Revised 2026.9.4 21:29
00500/00942_ichinichi