quicksilver
n.n. another name for liquid mercury. It is a very heavy, shiny metal that is used in thermometers and some types of batteries.
n. a liquid metallic element with the symbol Hg and atomic number 80. Historically used in various industrial and medicinal contexts before its toxic properties were fully understood.
The old thermometer was filled with quicksilver.
Before modern electronics, quicksilver was essential for the construction of accurate barometers and thermometers.
The alchemist's laboratory was filled with vials of quicksilver, though the volatile nature of the substance made it a constant source of concern for the apprentices.
From Middle English quyk silver, quyksilver, quikselver, from Old English cwicseolfor (“quicksilver”, literally “living silver”) (see Latin argentum vīvum) from its ability to move. See quick in the sense of "living". Cognate with Dutch kwikzilver, German Low German Quicksülver, German Quecksilber, Danish kviksølv, Norwegian Bokmål kvikksølv, Swedish kvicksilver. By surface analysis, quick (“living”) + silver.