What ⨆ means
It applies square union to a whole labeled family.
An indexed family is a collection whose members have labels, such as A₁, A₂, and A₃. “N-ary” means the operation takes many inputs at once; for sets, union collects their elements.
Why does ⨆ look different across formulas?
The font and math layout affect its appearance.
Plain-text fonts draw the glyph differently, and unsupported fonts may omit it.
Don't confuse it with
2Questions 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 2A06, 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 “n-ary square union operator”.
Linux
Ctrl+Shift+UType 2a06, then Enter or Space.
HTML
⨆CSS
\2A06LaTeX
Use \bigsqcup in LaTeX math mode for a variable-sized operator.
Codes and encoding1 code points
HTML decimal
⨆
HTML hex
⨆
CSS content
content: "\2A06";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%A8%86
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.