毫米水银柱 háomǐshuǐyínzhù millimeter of mercury Origin Definitions Defs Strokes Stroke Words Sentences Sents 毫米 háomǐ noun millimeter millimeter (mm); a unit of length equal to one-thousandth of a meter水银柱 水銀柱 shuǐyínzhù mercury column The column of mercury found in instruments like thermometers that expands or contracts to indicate a reading; also known as 汞柱 gòngzhù.