A differential operator symbol representing partial derivatives or boundaries in calculus and differential geometry.
Examples
Partial derivative notation
\frac{\partial f}{{\partial x}} = 2x + y
Mixed partial derivatives
\frac{\partial^2 f}{\partial x\partial y} = \frac{\partial^2 f}{\partial y\partial x}
Boundary of a set notation
\partial \Omega \text{ denotes the boundary of set } \Omega