時間

1. Origins, structure, and basic meaning

• Structure: 時間 (じかん) is a noun for duration, used both as an hour counter and as time allocated to an activity.
• Basic usage: 一時間ある quantifies one hour remaining before departure, while 読書の時間を作る makes time allocated to daily reading the object created.

2. Common pitfalls and similar expressions

• Measured duration and allocated time
  • In 一時間, 一 counts an exact number of hours, whereas 読書の時間 denotes time set aside for reading. The gloss “hour” should not be forced onto the latter.