Partial Derivative
For a function of more than one argument, the derivative with respect to one of them whilst treating the others as constants. Written as
\[
\frac{\partial f}{\partial x}
\]
For example, the partial derivative of
\[
f(x, y) = x^2 y
\]
with respect to \(x\) is
\[
\frac{\partial f}{\partial x} = 2 x y
\]
as opposed to
\[
\frac{\mathrm{d}f}{\mathrm{d}x} = 2 x y + x^2 \frac{\mathrm{d}y}{\mathrm{d}x}
\]
as determined by the product rule.