♃

The Greek letter Zeta with an abbreviation stroke, for Ζεύς (Zeús), the Greek equivalent to the Roman god Jupiter.[1] The form changed from Classical and early Medieval ⟨Ƶ⟩ to one with a more salient cross, ⟨♃⟩, in the 15th–16th century, at about the time that Christian crosses were added to ⟨☿⟩, ⟨♀⟩ and ⟨♄⟩, and so may have had a similar motivation.

Use of ♃ for Thursday, near the bottom of the calendar dial of this 16th-century clock-calendar.

♃

1. (astronomy, astrology) Jupiter.
2. (alchemy, archaic) tin.
3. (Can we verify⁽⁺⁾ this sense?) (botany, obsolete) herbaceous perennial plant.

   (the orbital period of Jupiter is 12 years)[2]

4. (rare) Thursday.

   Refers to the Latin phrase dies Iovis, which literally means "Jupiter's day".

• (astronomy): M_♃ – Jovian mass (as a unit of measurement; more commonly M_J).

R_♃ – Jovian radius (more commonly R_J).

• (alchemy): 🜩 – tin ore.

• 
  Late Classical and Medieval forms
• 
  A modern allograph of ♃ that more clearly reflects its origin in the letter 'Z'.
• 
  A decorative variant in the Netherlands
• 
  As a symbol for tin
• 
  An abstract variant
• 
  Symbol on a Tyrian-purple background
• 
  Mariner logo
• 
  Transit of Jupiter