增强 (zēngqiáng) means 'to strengthen or enhance' and focuses on increasing the degree or intensity of something abstract, like confidence, immunity, or trust. It differs from 加强 (jiāqiáng), which is broader and can also mean 'to reinforce' concrete systems or measures; 增强 is more about growth in quality or capability. Compared to 增长 (zēngzhǎng), which is about numerical or quantitative increase, 增强 is about qualitative improvement.