What 𝕦 means
Read it as a distinct variable; its formula gives it a local role.
Blackboard bold began as a chalkboard shortcut: doubling a stroke marked a bold mathematical letter. The mark moved into print, where familiar capital forms label number systems; Unicode later encoded a full mathematical alphabet that includes lowercase 𝕦.
Part of the collection
Don't confuse it with
1
Related characters
2
Questions people ask
1Can NFKC change 𝕦 into plain u?
Yes. NFKC compatibility normalization can map mathematical letters to ordinary Latin letters, erasing a distinction a formula may rely on.
More like this
11
How to type or find 𝕦
- Search it as
- double-struck u · blackboard bold u · mathbb u · uopf · fancy u · double-struck lowercase u
- Shows up in
- Anything that takes text · its shape is whatever your font draws
Windows (Word)
Windows
macOS
HTML
𝕦CSS
\1D566Codes and encoding1 code points
HTML decimal
𝕦
HTML hex
𝕦
CSS content
content: "\1D566";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%F0%9D%95%A6
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.