支援 (zhīyuán) means 'to support, assist, or provide aid', often in a practical, material, or emergency context — like sending resources to a disaster zone or backing a project. It is more concrete and action-oriented than 支持 (zhīchí), which is broader and can mean emotional or ideological backing. 协助 (xiézhù) is closer to 'assist' in a cooperative, hands-on way, while 救援 (jiùyuán) specifically means 'rescue' in urgent situations.