What 𝓫 means
The HTML entity 𝓫 renders as 𝓫.
The fancy b 𝓫 is Latin lowercase b drawn in bold script, a calligraphic style. In mathematical notation, that style distinguishes it as an identifier—a letter used as a name—while the surrounding formula gives it a role.
Why is it a separate math character?
It preserves letter styles that carry meaning in notation.
The script form belongs to mathematical typography, where type style helps distinguish identifiers. Its digital alphabet grew from scientific publishing: the STIX project began in 1995, its math-character proposal was submitted to Unicode in 1998, and Unicode accepted the mathematical alphabet proposal in 1999. STIX aimed to serve scientific and engineering authors from manuscript through print and digital publication; Unicode’s separate characters also preserve these styles in plain text.
Why does 𝓫 become a plain b?
Compatibility normalization can remove the style distinction.
Some text cleanup applies Unicode compatibility normalization, in forms called NFKC or NFKD, and maps this math-style character to ordinary Latin b. The letter remains, but its mathematical style distinction is lost.
Don't confuse it with
4Questions people ask
1Why does 𝓫 look different in different math fonts?
Unicode 18.0’s chart uses roundhand, a calligraphic pen style; Cambria Math and STIX Two Math default to chancery, another calligraphic style. The same encoded letter can therefore look different in a formula. A font without the glyph may show a blank or placeholder.
How to type 𝓫
𝓫\1D4EBCodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.