What 𝐃 means
It marks a D distinct from plain D in the formula. Its exact job depends on the notation chosen by the writer.
Some mathematical writing uses bold Latin letters for vectors (quantities with magnitude and direction); a plain letter may name a scalar, a quantity given by one number, or a vector's length. In a 1901 textbook on vector analysis, E. B. Wilson used that contrast. It is one convention, not a universal definition of 𝐃.
Why can 𝐃 behave oddly in ordinary text?
It is a mathematical letter, not a text font.
Unicode intends mathematical alphabet characters for formulas or technical notation. Adjacent single-letter variables are usually read as multiplication, so a whole word made from these letters may stop reading as a word. For a whole word used as a variable, use text styling instead.
NFKC and NFKD are compatibility-normalization forms that fold certain character distinctions. They change mathematical alphabets to plain Latin or Greek letters; this can erase a distinction that a formula relies on.
In formulas, bold type marks a mathematical distinction; outside them, this letter can look like decorative emphasis.
Bold alone does not tell you that 𝐃 is a vector; follow the formula's definitions.
Part of the collection
Don't confuse it with
1
More like this
12
How to type or find 𝐃
- Search it as
- bold d · boldface d · math bold d · unicode bold d · bold capital d · fancy d · bold d symbol
- Shows up in
- Anything that takes text · its shape is whatever your font draws
𝐃\1D403𝐃 in HTML text to produce this character.Codes and encoding1 code points
A visible symbol can contain several code points. JS .length counts UTF-16 units; UTF-8 counts bytes.