inside

1. Origins, structure, and basic meaning

• Structure: 内 refers to an inside or a position within a range and is read うち as an independent word.
• Basic usage: 参加者の内 means among the participants, while 案内(あんない) is the word for guidance.

2. Common pitfalls and similar expressions

• The upper limit of 以内
  • 以内(いない) includes the stated upper limit. 十分以内 means no more than ten minutes, including exactly ten minutes.