铅块 (qiān kuài) literally means 'lead block' — 铅 (qiān) is the chemical element lead, and 块 (kuài) is a common measure word for solid, chunky objects, here used as a noun meaning 'ingot' or 'solid mass'. Together, 铅块 refers specifically to a shaped, dense piece of metallic lead, typically cast into rectangular or cylindrical forms for industrial use. It is not a general term for any lead object (e.g., pencil lead is 石墨, not 铅), nor is it used for decorative or artistic lead pieces unless they match this standard ingot form.

This term appears most often in contexts involving metallurgy, recycling, radiation shielding, fishing weights, or ballast. Because lead is toxic, handling 铅块 requires safety precautions — a fact sometimes noted in technical or regulatory discussions. While rare in everyday conversation, it’s essential vocabulary for learners working with technical, scientific, or industrial Chinese texts.