段階

1. Origins, structure, and basic meaning

• Structure: In 段階 (だんかい), step 段 and level 階 combine to denote a stage.
• Basic usage: 段階 is one stage in an ordered process of change or procedure.

2. Common pitfalls and similar expressions

• One stage in an ordered progression
  • 段階に can mark reaching or acting at that level; it differs from an unrelated category in a classification.