What 𝕔 means
Its role comes from the formula around it.
Blackboard bold, or double-struck, began as a chalkboard workaround: doubling strokes made letters stand out when bold chalk was impractical. The convention carried into print. In math, letter styles can mark different meanings; familiar symbols for number sets use capitals. Fonts vary, but doubled strokes define the style. Unicode advises against using these characters as ordinary text styling.
Part of the collection
Don't confuse it with
1
Questions people ask
1Why does 𝕔 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 𝕔
- Also called
- blackboard bold c · double-struck c
- Search it as
- copf · mathbb · blackboard · double-struck · openface
- Shows up in
- Anything that takes text · its shape is whatever your font draws
Windows (Word)
Windows
macOS
HTML
𝕔CSS
\1D554Codes and encoding1 code points
HTML decimal
𝕔
HTML hex
𝕔
CSS content
content: "\1D554";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%F0%9D%95%94
1
On screen
1
Code points
2
JS .length
4
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.