What ⦜ means
It marks a 90° corner. The inner square shows that the angle's sides are perpendicular.
Euclid, an ancient Greek mathematician, treated right angles as a basic part of geometry. The square is a compact diagram cue for showing that relationship.
In some German-speaking and Polish geometry traditions, an arc with a dot also marks right angles.
Don't confuse it with
1Questions people ask
1Why does ⦜ show as an empty box?
The font may lack its glyph, so software can show a box or another fallback shape.
How to type ⦜
Windows (Word)
Alt+XType 299C, 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 “right angle variant with square”.
Linux
Ctrl+Shift+UType 299c, then Enter or Space.
HTML
⦜CSS
\299CHTML
Hexadecimal character reference: ⦜.
LaTeX
With unicode-math: \rightanglesqr.
Codes and encoding1 code points
HTML decimal
⦜
HTML hex
⦜
CSS content
content: "\299C";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%A6%9C
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.