What ⟰ means
Follow the notation around it. The glyph shows an upward, four-stroke arrow; the formula or diagram supplies the convention that gives it a specific role.
Don't confuse it with
4Questions 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 ⟰
Windows (Word)
Alt+XType 27F0, 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 “upwards quadruple arrow”.
Linux
Ctrl+Shift+UType 27f0, then Enter or Space.
HTML
⟰CSS
\27F0Codes and encoding1 code points
HTML decimal
⟰
HTML hex
⟰
CSS content
content: "\27F0";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%9F%B0
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.