hydrargyrum
n.
"mercury, quicksilver," 1560s, from Latin hydrargyrus, from Greek hydrargyros, from hydr-, stem of hydor "water" (see water, n.1) + argyros "silver" (see argent). Hence the chemical abbreviation Hg for the element mercury.
〔李〕n.[化] 汞，水银 [argyr=silver] ←hydr（o）-[GK] =water水；containing hydrogen氢（化）的