# What is the physical meaning of the von Kármán constant?

I know that the von Kármán constant ($k\approx0.4$) is useful in turbulence modeling. Something that bothers me is my lack of understanding where $k$ comes from or the physical meaning behind it. If $k$ is mainly used as a proportionality in the log-wind profile, why is it within the formulation of the Monin-Obukhov length? What is the physical meaning behind $k$? Is it a universal value (i.e. valid on extraterrestrial planets)? Why is $k$ considered important enough to be eponymous, while I see $\frac{1}{k}$ more often in formulations than $k$?