What 𝖾 means
No particular value comes with the letterform.
A mathematical alphabet is a set of letter shapes that notation can use to distinguish symbols. Here, sans-serif means the strokes lack small finishing lines; that style identifies the form, not what a particular variable stands for. The formula or field convention gives this e its role.
These styles came from mathematical typesetting; Unicode gave them a shared digital form. STIX, a project among scientific and technical publishers to gather the math characters their journals needed, began in 1995. Its math-alphabet proposal went to Unicode in 1998 and was accepted in 1999. MathML, a format for marking up web equations, also supported a fuller math character set so plain text could retain letter-style distinctions that matter in formulas.
Why does 𝖾 turn into e?
Compatibility normalization can erase its style.
NFKC and NFKD are compatibility-normalization forms; applying either maps this character to basic Latin e. NFC and NFD keep it. If the math style distinguishes symbols in your formula, that conversion erases the distinction.
In mathematical notation, the sans-serif style can distinguish a symbol instead of simply decorating a letter.
In ordinary prose, this separate character can disrupt search, restyling, and text processing.
Don't confuse it with
1Questions people ask
1Why does 𝖾 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 𝖾
𝖾\1D5BECodes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.