活動

1. Origins, structure, and basic meaning

• Structure: Spelling: 活動. Reading: かつどう. Core meaning: activity.
• Basic usage: Representative examples: 放課後に地域の清掃活動へ参加した / 朝から火山の活動を観測する作業が続いている.

2. Common pitfalls and similar expressions

• Human and natural activity
  • 活動 can describe organized human action such as cleanup work or an active natural phenomenon such as a volcano. The acting subject is not limited to people.