What ⟃ means
It marks an open-subset relation in specialized mathematics.
Those rules define which sets count as open; the surrounding definitions settle the relation’s exact meaning.
In the wider inclusion tradition, Joseph Gergonne used C for French «contient» (“contains”) in 1816–17; Ernst Schröder introduced another inclusion pair in 1890, after earlier use of < and >.
Formal notation for set theory and topology.
Don't confuse it with
1Questions people ask
1Why does ⟃ show as a box?
Usually a font-coverage issue. As of 2026-10-08, choose an OpenType math font that contains ⟃ in XeLaTeX or LuaLaTeX.
How to type ⟃
Windows (Word)
Alt+XType 27C3, 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 “open subset”.
Linux
Ctrl+Shift+UType 27c3, then Enter or Space.
HTML
⟃CSS
\27C3LaTeX
As of 2026-10-08, use `\subsetcirc` in LuaLaTeX or XeLaTeX with `unicode-math`.
Codes and encoding1 code points
HTML decimal
⟃
HTML hex
⟃
CSS content
content: "\27C3";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%9F%83
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.