昼・午・晝|ひるhiru[2]odaka (tail-high)

1. nounnoon; midday
   ケンは昼ひるまで家いえにいるでしょう。↗

   Ken will be at home until noon.
2. noun, adverbdaytime
   私は昼ひるも夜よるも彼女かのじょのことを考かんがえている。↗

   I think of her day and night.
3. nounlunch
   昼ひるはホットドッグを食たべたんだ。↗

   I ate a hot dog for lunch.

• Synonym正午しょうごWrittenWritten/formal: refers to exactly 12 noon, used in time announcements or formal contexts, e.g. 「正午のニュース」.
• Synonym真昼まひるWrittenWritten/formal: the middle of the day with the sun high overhead; adds emphasis, as in 「真昼の決闘」.
• Synonym日中にっちゅうWrittenWritten/formal: the daytime hours, as in 「日中の気温」 or 「日中は家にいない」.
• Synonym白昼はくちゅうWrittenWritten/formal: broad daylight, often in crime reporting, as in 「白昼堂々」.
• Relatedお昼おひるCasualPolite colloquial word for midday or lunch, as in 「お昼にしよう」.
• Related昼間ひるまNeutralNeutral: the whole daytime from morning to evening, the counterpart of 「夜」.
• Related昼過ぎひるすぎNeutralNeutral, everyday word for the time just past noon, e.g. 「昼過ぎに会おう」; it points to the hours after midday rather than noon itself.
• Related午刻ごこくWrittenArchaic written term for around noon; seen in old or archaizing texts. In everyday speech say 「正午」.
• Related昼日中ひるひなかWrittenWritten: emphasizes broad daylight, often with the indignant tone of 'right in broad daylight, no less'.
• Related亭午ていごWrittenLiterary Sino-Japanese word for high noon, when the sun stands highest; found in literary or archaizing prose. Say 「正午」 in daily speech.
• Related昼中ひるなかNeutralNeutral: during the day, while the sun is up; less common — in everyday use prefer 「昼間」.

Use 「昼」 as the default for midday and daytime. Pick 「昼間」 for the whole daytime, 「正午」 for exactly 12 noon, 「お昼」 for lunch, and 「白昼」 for broad daylight; for the time just after noon, say 「昼過ぎ」. Most of the rest are written or archaic alternatives.

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

1. ひる。昼間ひるま。
2. 昼食ちゅうしょく。お昼ひる。