半日

1. Origins, structure, and basic meaning

• Structure: 半日, read はんにち, means roughly half a day or a morning or afternoon portion of it.
• Basic usage: In 部屋の片付けだけで半日もかかってしまった。, tidying the room alone is said to have taken as much as half a day.

2. Common pitfalls and similar expressions

• Duration and leave units
  • 半日もかかってしまった conveys that the task took longer than expected. 半日休暇 refers to a morning or afternoon off, so neither use should automatically be converted into exactly twelve hours.