‘Zāo pò’ literally combines ‘zāo’ (dregs, lees — the solid residue left after brewing alcohol or processing grains) and ‘pò’ (lees, residue — especially from soybean or rice fermentation). Together, they form a metaphorical noun meaning ‘dross’ or ‘worthless remnants’ — used primarily to describe outdated, superstitious, or harmful ideas, customs, or cultural elements that should be discarded. Historically, it appears in phrases like ‘取其精华，去其糟粕’ (‘take the essence, discard the dross’), emphasizing critical inheritance of tradition.

The term carries a formal, often academic or ideological tone and is common in discussions about cultural reform, education, and historical evaluation. While rooted in material residue (e.g., fermentation byproducts), its modern usage is almost exclusively figurative — referring to obsolete beliefs, feudal practices, or unscientific notions. It rarely refers to physical waste today, and never to animal-related substances despite its etymological link to brewing (which may involve animal-derived enzymes in traditional contexts).