respond

1. Origins, structure, and basic meaning

• Structure: 応 has 7 strokes and the on-reading おう. 対応 (たいおう) and 反応 (はんのう) both concern responses but have different focuses.
• Basic usage: 対応 concerns handling a situation or inquiry; 反応 concerns a reaction to something such as a proposal or call.

2. Common pitfalls and similar expressions

• Handling a situation and showing a reaction
  • 停電にも落ち着いて対応した means responded calmly even to a power outage. 問い合わせへの対応 refers to handling inquiries.
  • 皆の反応は意外に静かでした means that everyone's reaction was unexpectedly quiet. 呼びかけても反応がない means there is no response even when someone calls.