What ؆ means
It marks the third root of an expression. An Arabic treatise dated 1004–1005 CE explains cube-root extraction with words and worked rules. A source from the late twelfth century in the Maghreb (North Africa) records a different root mark based on the Arabic letter ج, called jīm; that mark indicates a square root, not a cube root.
Arabic mathematical writing also used prose and letter-based marks for roots. Many Arabic mathematical signs are linked with the Amman agreement of 1987.
In mixed-direction expressions, let the text system place the sign. Its Arabic-Indic index remains unmirrored.
A specialist sign for mathematical notation written with the Arabic script.
If it appears alone, add an equation or label; the sign does not show which expression is under the root.
Don't confuse it with
2Questions people ask
1Why does ؆ show as a box on some devices?
Because that device's fonts have no glyph for it. The character is still correct and still copies correctly — the box is a missing glyph, not a broken character.
How to type ؆
؆\0606Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.