'Fēng dǐ' literally means 'cover bottom' — 'fēng' refers to the cover or binding of a book, and 'dǐ' means 'bottom' or 'base'. Together, they specifically denote the back cover of a printed book, magazine, or similar bound publication. Unlike the front cover (封面), which often features prominent titles and artwork, the back cover typically displays supplementary information such as author bios, blurbs, barcodes, publisher logos, or promotional text.

This term is used exclusively in publishing and library contexts, not for digital books or loose documents. It’s a standard, neutral term appropriate for formal and informal descriptions of physical publications. You’ll commonly see it in book design discussions, cataloging instructions, or when describing how content is distributed across a book’s physical structure — for instance, where an ISBN appears or where a short synopsis is placed for marketing purposes.