Origin Story
Mercurial is likewise a personality word that comes from a planet and a god. In Roman mythology, Mercury was the messenger of the gods — winged at the feet, darting across the sky as the swiftest of them all. The planet named after him, closest to the sun, seemed to shift its place in the night sky faster than any other. So astrology held that a person born under Mercury's influence was quick-minded and witty, but by the same measure moody, fickle, and hard to pin down. From this the word mercurialis ("of Mercury") came to mean "volatile, quick."
Mercury's name also links to commerce (merchant, commerce), because he was the god of traders and travelers as well. And the liquid metal mercury — which flows and rolls about quickly at room temperature — took the same name in a nod to his swiftness.
-
Online Etymology Dictionarymercurial (adj.): mid-14c., "pertaining to the planet Mercury," from Latin mercurialis "of Mercury," from Mercurius; sense of "sprightly, volatile, quick" (1590s) is from the supposed influence of the planet on those born under it
-
Merriam-Webster Dictionarymercurial: from Latin mercurialis of Mercury, from Mercurius Mercury; from the lively, changeable qualities attributed to those born under the planet
-
Oxford English Dictionarymercurial: from Latin mercurialis "of Mercury," referring to the supposedly volatile temperament of those born under the planet Mercury
Word Evolution
Words from the Same Root
Memory Hook
Remember mercurial as the volatile influence of Mercury, the fastest planet — as hard to pin down as the metal mercury itself.
""To the fastest-moving of stars, people likened the most fickle of hearts.""
