People in the past boiled water in a small tea pan on the stove.
Tips
mistakes
Same character as the sound word 铛, the clang of metal, but a cooking pan is read chēng. If the sentence is about food or a pan, it is chēng; if it is about a noise, it is dāng.
usage
This reading rarely stands alone. It lives inside pan names: 饼铛, a flatbread griddle, and 电饼铛, the electric version sitting in a lot of Chinese kitchens. Older writing adds 茶铛 and 药铛, small pans for boiling tea or medicine.
Left metal radical, the indexing element in its five-stroke side form. Here it is literal cookware: a 铛 is a metal pan, which files it with 锅 (pot), 铲 (spatula) and 锉 (file).
Right 当 is doing pure sound duty, and the fit is loose: it reads dāng while this pan sense reads chēng, a drift the character kept when the two senses parted. Compare 铜 (copper), phonetic only.