日に日に|ひにひにhinihini[0]heiban (flat)

1. adverbday by day; by the day
   患者かんじゃは日ひに日ひによくなっていった。↗

   The patient was recovering daily.
2. adverbdaily; every day

• Synonym日増しにひましにNeutralStresses day-by-day intensification, typically of increasing degree, as in 「日増しに寒くなる」; largely interchangeable with 「日に日に」.
• Synonym一日増しにいちにちましにCasualColloquial and rarely used; stresses day-by-day increase. In everyday speech, 「日増しに」 or 「日に日に」 is more natural.
• Synonym日に増しNeutralClose in meaning to 「日増しに」, but the particle 「に」 sits in a different position; used less often.
• Synonym日にましNeutralThe kana spelling of 「日に増し」 above; same meaning, but less common.
• Related逐日ちくじつWrittenWritten/formal prose for change unfolding as the days pass; in everyday speech, 「日に日に」 is the usual choice.
• Related日ごとにひごとにNeutralCovers 'every day' and day-by-day change, with the focus on gradual daily progress; interchangeable with 「日に日に」.
• Related日一日WrittenWritten/formal prose, usually as 「日一日と」; synonymous with 「日に日に」.

For day-by-day change, 「日に日に」 and 「日増しに」 are the everyday choices and are often interchangeable; in written or formal prose, prefer 「日一日と」 or 「逐日」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. その日毎ひごとに。一いち日にち毎ごとに。