Let $y = f(x)$ be some function, with the second and third derivatives of $f(x)$ in the neighborhood of some point $c$:
$d^{(2)} = \frac{d^2 f}{dx^2}$
$d^{(3)} = \frac{d^3 f}{dx^3}$
Define quantity $Q$:
$Q(c) = -f(c)\frac{d^{(3)}} {d^{(2)}}$
In economics, if $f(x)$ is a utility function, then quantity $Q$ is known as the "relative prudence". Is $Q$ known to have any significance mathematically? That is, if you are not an economist, would the formulation of $Q$ ring any bells in your head which would associate $Q$ with some mathematical concept or term?