What ≔ means
It defines a term or assigns a value. In mathematics, A ≔ B defines A as B; it isn't an equality claim.
In programming, : assigns the right-side value to the left-side variable. Thus x : x 1 updates x, while x x 1 is false.
Algol, a programming language, chose colon-equals for assignment in 1958.
Part of the collection
Don't confuse it with
3
Equal To By Definition
Another definition mark, with the colon after the equals sign.
Equals Sign
Ordinary equality; ≔ marks a definition.
: Two characters; ≔ is one symbol.
Related characters
1
Questions 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.
More like this
11
How to type or find ≔
- Also called
- coloneq
- Search it as
- := · definition symbol · assignment operator
- Shows up in
- Anything that takes text · its shape is whatever your font draws
Windows (Word)
Windows
HTML
≔CSS
\2254Windows Word
Type 2254, then press AltX.
macOS
Enable Unicode Hex Input, hold Option, and enter 2254.
Linux GTK
Press CtrlShiftU, enter 2254, then Space or Enter.
Plain text
If ≔ shows as a box, the font may lack it; : is a fallback.
Codes and encoding1 code points
HTML decimal
≔
HTML hex
≔
CSS content
content: "\2254";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%89%94
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.