force · momentum

1. Origins, structure, and basic meaning

• Structure: 勢 conveys force or momentum; 勢い is read いきおい.
• Basic usage: 勢い describes a team's momentum or the force of flowing water, while 大勢 refers to a large number of people.

2. Common pitfalls and similar expressions

• On-readings in words
  • 大勢 is read おおぜい, and 姿勢 is read しせい. Distinguish ぜい from せい in these words.
• Momentum and posture
  • 勢い is force or momentum in movement; 姿勢 is bodily posture or an attitude toward an activity.