心脏 (xīn zàng) literally means 'heart organ'—it combines 心 (xīn), meaning 'heart' in both anatomical and emotional senses, and 脏 (zàng), meaning 'internal organ'. Together, they specifically refer to the muscular organ that pumps blood through the circulatory system. Unlike 心 alone—which can also mean 'mind', 'core', or 'feeling'—心脏 is strictly anatomical and used in medical, biological, and health-related contexts.

This term appears frequently in discussions about physical health, fitness, disease, and anatomy—for example, in phrases like 心脏病 (heart disease) or 心脏跳动 (heartbeat). It’s a formal, standard term taught early in Chinese science curricula and used in hospitals, textbooks, and public health announcements. Learners should avoid using 心脏 when expressing emotions; for those meanings, 心 alone is appropriate and more natural.