繁衍 (fányǎn) is a formal, literary verb meaning 'to multiply' or 'to propagate', especially in biological contexts. It describes the natural process by which living organisms produce offspring and increase their population over generations. The first character 繁 (fán) means 'abundant', 'numerous', or 'flourishing', while the second character 衍 (yǎn) means 'to extend', 'to spread', or 'to develop'. Together, they evoke the idea of life expanding outward and increasing in number — not merely reproducing once, but sustaining and growing a lineage or species.

This word is commonly used in scientific, ecological, and environmental discourse — for example, when discussing endangered species, invasive species, or ecosystem balance. It appears frequently in textbooks, news reports on conservation, and documentaries. While it can technically apply to humans, it’s rarely used that way in everyday speech; instead, words like 生育 (shēngyù) or 繁殖 (fánzhí) are more common for human reproduction. 繁衍 carries a neutral-to-positive connotation, suggesting natural continuity and vitality.