What 𝓲 means
As of 2026-09-28, in Word for Windows, enter 1D4F2 and press Alt+X.
What does bold script i mean?
It marks a mathematical alphabet; the formula says what this i represents.
The glyph joins lowercase Latin i in a bold, cursive style. In a formula, that style can distinguish this symbol from plain or italic i; the letterform is a cue, while the equation supplies the value or role.
Mathematical letter styles grew through typesetting practice. When the American Mathematical Society adopted TeX, a system for typesetting technical documents, its available symbols lacked several alphabets used in its publications. With Donald Knuth's help, type designer Hermann Zapf created Euler's mathematical scripts, including an upright cursive face for formulas, not running text. Unicode's math alphabets preserve such style distinctions as characters.
Why does 𝓲 become plain i?
Compatibility normalization can fold its style away.
NFKC is a Unicode cleanup form that maps mathematical styled letters to base Latin or Greek letters; for 𝓲, the result is plain i. That can erase a distinction a formula relies on.
For math or technical notation; use ordinary letters with text styling for prose decoration.
Don't confuse it with
2Questions people ask
1Why does 𝓲 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.
How to type 𝓲
𝓲\1D4F2Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.