What ⫔ means
It combines two set-inclusion directions in one sign.
A superset contains every element of another set; a subset contains only elements from it. The surrounding notation supplies the intended relation.
Which set-relation signs are related?
Their order, repetition, and spacing vary.
A 1999 Unicode proposal groups these forms as subset/superset relations; a 2003 ISO/IEC 9573-13 table records ⫔ under the entity name supsub.
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 2AD4, 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 “superset above subset”.
Linux
Ctrl+Shift+UType 2ad4, then Enter or Space.
HTML
⫔CSS
\2AD4Codes and encoding1 code points
HTML decimal
⫔
HTML hex
⫔
CSS content
content: "\2AD4";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%AB%94
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.