What 𝓑 means
Its letter style is part of the mathematical notation.
The Latin B’s mathematical history predates this styling: François Viète’s 1591 algebra used capital consonants such as B for known quantities and vowels for unknowns. Later mathematical fonts used script and bold styles to distinguish symbol classes.
Math fonts vary in the bold-script strokes; Unicode does not prescribe a single drawing.
Don't confuse it with
4𝐁𝑩𝓐𝓒
Mathematical Bold Capital B
shares “b”, “bold”, “capital”, “mathematical”
Mathematical Bold Italic Capital B
shares “b”, “bold”, “capital”, “mathematical”
Mathematical Bold Script Capital A
shares “bold”, “capital”, “mathematical”, “script”
Mathematical Bold Script Capital C
shares “bold”, “capital”, “mathematical”, “script”
Questions people ask
1Can I use 𝓑 to style a word?
It displays, but Unicode intends these alphabets to mark mathematical distinctions, not to style running prose. Use a plain B with text formatting for a word.
How to type 𝓑
Windows (Word)
Alt+XType 1D4D1, then Alt+X to get 𝓑.
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 “mathematical bold script capital b”.
Linux
Ctrl+Shift+UType 1d4d1, then Enter or Space.
HTML
𝓑CSS
\1D4D1LaTeX (unicode-math)
For 𝓑, use `\mbfscrB` with the `unicode-math` package.
Text normalization
NFKC is a Unicode text-normalization form; it can turn 𝓑 into plain B and erase the mathematical distinction.
Codes and encoding1 code points
HTML decimal
𝓑
HTML hex
𝓑
CSS content
content: "\1D4D1";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%F0%9D%93%91
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.