What ≐ means
It marks convergence or an asymptotic relation. The surrounding formula and the author's definitions tell you which reading applies.
Dotted equality is part of a longer history of competing limit notations. American mathematical texts used it for “converging to” a limit around 1902; arrow notation later became more widely adopted.
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 2250, 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 “approaches the limit”.
Linux
Ctrl+Shift+UType 2250, then Enter or Space.
HTML
≐CSS
\2250LaTeX
Use \doteq inside a math environment.
HTML
Use ≐, ≐, ≐, or ≐.
Linux Unicode input
In Linux Unicode input, press Ctrl+Shift+U, type 2250, then press Enter.
Codes and encoding1 code points
HTML decimal
≐
HTML hex
≐
CSS content
content: "\2250";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%89%90
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.