The character ∂ (html element: ∂ or ∂, unicode: U+2202) or
∂
is a stylized d mainly used as a mathematical symbol to denote a partial derivative such as
∂
z
∂
x
(read as "the partial derivative of z with respect to x"). The symbol was originally introduced by Legendre in 1786, but only gained popularity when it was used by Jacobi in 1841.
∂ is also used to denote the following:
The Jacobian,
∂
(
x
,
y
,
z
)
∂
(
u
,
v
,
w
)
.
The boundary of a set in topology.
The boundary operator on a chain complex in homological algebra.
The boundary operator of a differential graded algebra.
The Dolbeault operator on complex differential forms.
The symbol may be referred to as "del", "dee", "partial dee", "partial" (especially in LaTeX), "round d", "curly dee", or "dabba".
The lowercase Cyrillic De looks similar when italicized.
