成人

1. Origins, structure, and basic meaning

• Structure: 成人 (せいじん) means an adult or becoming one socially or legally.
• Basic usage: A course targets adults; a story follows growth until the protagonist reaches adulthood.

2. Common pitfalls and similar expressions

• Adults as an audience and adulthood as developmental endpoint
  • Noun 成人を対象に is a group; verb 成人する is change of status. Legal age depends on jurisdiction and period.