Symbols for angles

I was looking around in the Unicode block for miscellaneous symbols, U+2600, after I needed to look something up, and noticed there are four astrological symbols for angles: ⚹, ⚺, ⚻, and ⚼.

⚹ ⚺ ⚻ ⚼

These symbols are mysterious at first glance but all make sense in hindsight as I’ll explain below.


The first symbol, ⚹, U+26B9, is self-explanatory.  It is made of six 60° angles and is called a sextile after the Latin word for six.


The second symbol, ⚺, U+26BA, is less obvious, though the name is obvious: semisextile is the top half of a sextile, so it represents an angle half as wide.

The symbol looks like ⊻, U+22BB, the logic symbol for XOR (exclusive or), but is unrelated.


The third symbol, ⚻, U+26BB, represents an angle of 150°, the supplementary angle of 30°. Turning the symbol for 30° upside down represents taking the supplementary angle.

The symbol looks like ⊼, U+22BC, the logic symbol for NAND (not and), but is unrelated.

I’ve run into the name quincunx before but not the symbol. Last fall I wrote a post about conformal mapping that mentions the “Peirce quincuncial projection” created by Charles Sanders Peirce using conformal mapping.

Charles Sanders Peirce's quincuncial project
Because the projection was created using conformal mapping, the projection is angle-preserving.

The name of the projection comes from another use of the term quincunx, meaning the pattern of dots on the 5 side of a die.


The final symbol, ⚼, U+26BC, represents an angle of 135°. A little thought reveals the reason for the symbol and its name. The symbol is a square and half a square, representing a right angle plus half a right angle. The Latin prefix sesqui- means one and a half. For example, a sesquicentennial is a 150th anniversary.

One thought on “Symbols for angles

  1. Off-topic, but the term “quincunx” makes me think of a wonderful late-‘80s novel, “The Quincunx”, by Charles Palliser, which is simultaneously a masterful recreation of a 19th century Dickens novel, and a subtle deconstruction of same. A great read…

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