mercury1
Pronunciation: /ˈməːkjəri/
noun
- the chemical element of atomic number 80, a heavy silvery-white metal which is liquid at ordinary temperatures: we completed a programme to test all of our coal-fired plants for mercury and other air-toxins (Symbol: Hg)Also called quicksilver.
- the column of mercury in a thermometer or barometer, or its height as indicating atmospheric temperature or pressure: coastal sunshine sends mercury soaring
- historical mercury or one of its compounds used medicinally, especially to treat syphilis: one wonders how many unfortunates owed their demise to his prescription of mercury to clarify the spleen

Origin:
Middle English: from Latin Mercurius (see Mercury (sense 1))