∂


The character ∂ is a stylized cursive d mainly used as a mathematical symbol. This symbol can be used variously to denote a partial derivative such as , the boundary operator in a chain complex, or the conjugate of the Dolbeault operator on smooth differential forms over a complex manifold.

History

The symbol was originally introduced in 1770 by Nicolas de Condorcet, who used it for a partial differential, and adopted for the partial derivative by Adrien-Marie Legendre in 1786.
It represents a specialized cursive type of the letter d, just as the integral sign originates as a specialized type of a long s.
Use of the symbol was discontinued by Legendre, but it was taken up again by Carl Gustav Jacob Jacobi in 1841, whose usage became widely adopted.

Names and coding

The symbol is variously referred to as
"curly d", "rounded d", "curved d", "dabba", or "Jacobi's delta", or as "del".
It may also be pronounced simply "dee", "partial dee", "doh", or "die"
The Unicode character is accessed by HTML elements ∂ or ∂, the LaTeX symbol is accessed by \partial.

Uses

∂ is also used to denote the following: