☿ is an astrological and astronomical symbol representing the planet Mercury.
The planet was named after the Roman messenger god, Mercury, whom the Romans identified with the Greek god Hermes. The symbol ☿ is a simplified version of caduceus (a staff entwined by two serpents) carried by Mercury/Hermes. In alchemical tradition, Mercury was associated with quicksilver (mercury).
In Romance languages, the word for Wednesday originates from Latin dies Mercurii, i.e. “day of Mercury” (mercredi, mercoledì, miércoles, miercuri). In Germanic laguages, this day became connected with god Odin or Wōden (onsdag, Wednesday, woensdag).
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