定員

1. Origins, structure, and basic meaning

• Structure: The spelling is 定員, read ていいん, and it combines 定, meaning set or determine, with 員, meaning member or person.
• Basic usage: The basic sense of 定員 is the fixed maximum number of people permitted in a course, event, facility, or similar setting.

2. Common pitfalls and similar expressions

• A fixed limit rather than the current headcount
  • Both examples use the form 定員. It identifies a predetermined capacity, and 定員に達する means that this limit has been reached.
• Thirty course places and closed registration
  • この講座の定員は三十人です。 — The capacity of this course is thirty people.
  • 参加者が定員に達したため、受付を終了しました。 — Registration closed after enrollment reached capacity.