What 𝒶 means
It is a script-style a; the formula decides what it stands for.
The math script a is one of the calligraphic Latin alphabets used for single-letter symbols. A writer may reserve it for one variable and use plain a or italic 𝑎 for another; no style has a universal value such as a particular number.
Why give math letters separate script forms?
So plain text could keep mathematical distinctions.
By 1999, a proposal from the STIX project, a group working on scientific and technical publishing, documented demand for complete bold, italic, and script alphabets in math. It argued that changing a letter’s style can change which variable it names, so plain text needs to retain that distinction.
In formulas, treat the script as part of the symbol; for ordinary prose, use a regular a with font styling.
Compatibility normalization such as NFKC can fold 𝒶 to plain a and erase that distinction.
Part of the collection
Don't confuse it with
1
Related characters
3
a under compatibility normalization. They share the base letter, but the script style can distinguish its role in a formula.Questions people ask
2Why does 𝒶 look different in fonts?
Script letters can appear in roundhand, a flowing hand, or chancery, a more formal calligraphic hand. Unicode 18.0 charts show roundhand, while Cambria Math and STIX Two Math default to chancery. The font changes the look, not the encoded character.
Does 𝒶 become plain a when text is normalized?
It can. Unicode cleanup forms NFKC and NFKD can fold this character to plain a; NFC leaves the style distinction intact. That fold can erase a distinction a formula depends on.
More like this
11
How to type or find 𝒶
- Search it as
- calligraphic a · math calligraphy · fancy lowercase a · script lettering
- Shows up in
- Anything that takes text · its shape is whatever your font draws
𝒶\1D4B61D4B6 without U+, then press Alt+X; Word converts the hexadecimal value to 𝒶.Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.