What ℒ means
It usually names the Laplace transform.
The transform represents a function through an integral. Its mathematical history includes work by the mathematician Euler and an application by mathematician Bateman in 1910.
This script form developed through changing Latin handwriting styles; capital L had no single fixed design.
Mathematical notation; it marks a named operator, not decoration.
Check the author's definition; ℒ can name something else.
Don't confuse it with
2Combination ideas
1Laplace transform applied to f(t).
Questions people ask
1Why does ℒ 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 ℒ
Windows (Word)
Alt+XType 2112, then Alt+X to get ℒ.
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 “script capital l”.
Linux
Ctrl+Shift+UType 2112, then Enter or Space.
HTML
ℒCSS
\2112LaTeX
Use \mathcal{L} in a math environment.
Codes and encoding1 code points
HTML decimal
ℒ
HTML hex
ℒ
CSS content
content: "\2112";
Each escape is closed by the next backslash; a trailing space is needed before a literal hex digit.
URL encoded
%E2%84%92
1
On screen
1
Code points
1
JS .length
3
UTF-8 bytes
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.