What ℸ means
It is the fourth of set theory's Hebrew-letter signs. Since Georg Cantor, mathematicians have written the sizes of infinite sets (transfinite cardinals) with Hebrew letters: ℵ (aleph) for the aleph numbers, ℶ (beth) for the beth numbers, ℷ (gimel) for the gimel function in cardinal arithmetic.
Dalet, the next letter of the Hebrew alphabet, completes the set and is available in standard math typesetting, but it has no single agreed meaning. When an author uses ℸ, the text defines it, so look for that definition nearby.
Is ℸ the same as the Hebrew letter ד?
No: same origin, different characters. ד (dalet) is the fourth letter of the Hebrew alphabet, has the numeric value 4 and is written right to left; its name is linked to the Hebrew word for "door". ℸ copies its shape as a left-to-right math sign so it sits properly inside formulas.
Use ד when writing Hebrew words: ℸ breaks search, spellcheck and text direction there. Greek Δ and Latin D descend from the same ancient Phoenician letter as ד.
Specialist mathematical notation; almost never seen outside set theory papers and textbooks.
Don't use ℸ for the Hebrew letter ד in Hebrew text.
Part of the collection
Don't confuse it with
2
Related characters
4
Combination ideas
3Questions people ask
2Will I see ℸ in everyday text?
Almost never. It lives in advanced set theory, and even there it is rarer than ℵ, ℶ and ℷ.
Why does it show as a box?
Your font lacks it. Math fonts and fonts with good Unicode coverage include it.
More like this
13
How to type or find ℸ
- Also called
- daleth symbol · dalet sign
- Search it as
- daleth · ℸ · hebrew math symbol · set theory symbol · transfinite cardinal · \daleth
- Shows up in
- Anything that takes text · its shape is whatever your font draws
ℸ\2138Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.