☉

The shield of the sun god Apollo, with a boss in the center. Medieval replacement of ⟨🜚⟩, the sun with a single ray, which in ancient times had replaced a sun orb surrounded by multiple rays.^[1]

Compare the Egyptian hieroglyph ⟨⟩ and the Chinese character ⟨⟩, both of which mean 'sun' and 'day'.

☉

1. (astronomy, astrology) Sol, the Sun.

   A subscript to variables in mathematical equations, such as π_☉ (solar parallax).

   • 1803, Robert Patterson, The Papers of Thomas Jefferson, volume 40 (in English), Princeton University Press, published 2013, page 71:

     Suppose the apparent angular distance of the sun & moon's nearest limbs [...] to be 110°.2′.30″ the app. alt of ☉'s lower limb measuring 20°.40′ and that of ☽'s lower limb 35°.24′

   • 1797, Sigismund Bacstrom, transl., Chemical Moon-Shine: Wherein is Demonstrated the True Subject of Philosophy, Where We are to Look for it, & How it is to be Prepared:

     The matter must be collected when the Ram is grasing. |: i.e. ☉ in ♈︎ :|

   • 1652, Elias Ashmole, Theatrum Chemicum Britannicum, page 451:

     Witneſſe their power in Plants, Herbes, Corne, and what is Vegitable, whoſe Seeds diverſly proſper, or decay, according to the ſtate of the ☽ with the ☉ at the time of their ſowing.

2. (astronomy) solar mass.

   Synonym: M_☉

   • 1939, Oppenheimer & Volkoff, “On Massive Neutron Cores”, in Physical Review, volume 55:

     For masses under ${\displaystyle \textstyle {\frac {1}{3}}}$☉ only one equilibrium solution exists

3. (botany) annual.^[2]
4. (alchemy) gold.
   • 1650, Paracelsus, “Of the Nature of Things”, in John French, transl., A New Light of Alchymie, page 73:

     But that the five leſſer, and impurer Metalls, viz. ♀ ♃ ♄ ♂ and ☿ may be tranſmuted into the greater, pureſt, and moſt perfect Metalls, viz. into ☉ and ☾, it cannot be done without the Tincture, or Philoſophers ſtone.

5. (rare) Sunday.

   Refers to the Latin phrase dies Solis, which literally means "Sun's day".

6. (philately) cancellation (with an ordinary post-office cancellation mark).
7. (chemistry, obsolete) hydrogen (Daltonian symbol).

   Technically, this should be red: ☉. May also be typeset ⊙.

• (sun, daytime): ☼
• (sun, gold): 🌞︎, 🜚 (obsolete)

• (astronomy): M_☉ – solar mass (as a unit of measurement for the masses of stars)

L_☉ – solar luminosity (as a unit of measurement).

R_☉ – solar radius (as a unit of measurement).

S_☉ – solar constant (as a unit of measurement).

• (alchemy): ☉⃞ (gold leaf, gold foil)

• (botany): ⚇ (biennial)
• (astrology): 🝵 (Solar eclipse)

• An abstract variant
• A decorative variant in the Netherlands
• As a symbol for gold
• Symbol on a gold background

• 𓇳 (hieroglyph for Sun)
• ⊙ (mathematics, computing)

☉

1. (cartography): city center

☉ m sg (genitive ☉lis); third declension

1. (alchemy) abbreviation of sol (“sun”)
   • 1688, Caspar Cramer, Collegium chymicum, page 6:

     Sic ſunt homines, qui ad lumen candelæ non autem ☉lis cœcutiunt, morbus nyctalopia dicitur.

     Thus there are men who are blind to the light of a candle but not of the sun; the disease is called nyctalopia.

Third-declension noun, singular only.

Third-declension noun, singular only.

• ☉is

☉ n (genitive ☉rī); second declension

1. (alchemy) abbreviation of aurum (“gold”)
   • 1701, Johann Christoph Sommerhoff, Lexicon pharmaceutico-chymicum latino-germanicum & germanico-latinum [Pharmaceutico-Chemical Lexicon, Latin-German and German-Latin], page 34:

     Aurum fulminans fit ex ☉ro in 🜆egis ſoluto

     Fulminating gold is made from gold dissolved in aqua regia

Second-declension noun (neuter).