What ⋱ means
It stands for omitted entries on a down-right diagonal. The dots show a pattern continuing through later rows and columns without listing every value. In LaTeX math mode, \ddots sets this matrix ellipsis.
Mathematician Arthur Cayley’s 1855 work helped establish matrix theory, the mathematical study of these grids.
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 22F1, 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 “down right diagonal ellipsis”.
Linux
Ctrl+Shift+UType 22f1, then Enter or Space.
HTML
⋱CSS
\22F1LaTeX
In math mode, `\ddots` makes the falling diagonal. The mathdots package also provides `\iddots` for the opposite slant.
Codes and encoding1 code points
HTML decimal
⋱
HTML hex
⋱
CSS content
content: "\22F1";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%8B%B1
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.