What ⊏ means
Read the definition attached to the relation.
In Barendregt’s book on lambda calculus, a formal system for describing functions, ⊏ labels a partial order on an abstract set. Such an order can leave some pairs incomparable, so the symbol there does not compare numbers.
Unicode 18.0’s mirror data pairs ⊏ with ⊐ for right-to-left layout; a renderer may show the opposite-facing glyph while the stored character remains ⊏.
Don't confuse it with
1Questions 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 228F, 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 “square image of”.
Linux
Ctrl+Shift+UType 228f, then Enter or Space.
HTML
⊏CSS
\228FLaTeX
Use `\sqsubset` in math mode.
HTML
HTML uses the named entity `⊏`.
Codes and encoding1 code points
HTML decimal
⊏
HTML hex
⊏
CSS content
content: "\228F";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8A%8F
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.