複合

1. Origins, structure, and basic meaning

• Structure: 複合 (ふくごう) is a nominal stem for a state or material made by combining multiple distinct elements.
• Basic usage: 複合材で板を作る identifies a material combining several substances, while 複合的な原因 says several causes jointly contributed to an accident.

2. Common pitfalls and similar expressions

• Composite material and combined causes
  • 複合材 is a physical product, whereas 複合的な原因 combines abstract factors. The latter does not involve materials being physically mixed.