What ⬸ means
It is a left-pointing math arrow with a dotted stem. The formula around it specifies the relation.
Where did this arrow come from?
A 2001 proposal argued that additional mathematical symbols should reflect existing mathematical literature and support MathML, a format for web formulas. In 2009, a STIX mathematical-font proposal grouped the dotted-stem arrow with other directional dotted arrows.
Technical and uncommon in ordinary messages.
Without surrounding notation, it does not mean “back” or “undo.”
Don't confuse it with
1Questions people ask
1Why does ⬸ show as a box?
The selected font may lack its glyph, so the app shows a replacement box or fallback mark.
How to type ⬸
Windows (Word)
Alt+XType 2B38, then Alt+X to get ⬸.
Windows
Win+Rrun charmap for the full table, or use the emoji picker's Ω symbols tab (Win + .).
macOS
Control+Command+SpaceOpen the character viewer and search “leftwards arrow with dotted stem”.
Linux
Ctrl+Shift+UType 2b38, then Enter or Space.
HTML
⬸CSS
\2B38Codes and encoding1 code points
HTML decimal
⬸
HTML hex
⬸
CSS content
content: "\2B38";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%AC%B8
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.