  P. Tur\'an was the first to derive lower estimations on the uniform norm of
the derivatives of polynomials $p$ of uniform norm $1$ on the interval
I:=[-1,1] and the disk D:=$\{z \in C~:~|z| \le 1\}$, under the normalization
condition that the zeroes of the polynomial p in question all lie in I or D,
resp. Namely, in 1939 he proved that with n:=deg p tending to infinity, the
precise growth order of the minimal possible derivative norm is $\sqrt{n}$ for
I and n for D.
  Already the same year J. Er\H{o}d considered the problem on other domains. In
his most general formulation, he extended Tur\'an's order n result on D to a
certain general class of piecewise smooth convex domains. Finally, a decade ago
the growth order of the minimal possible norm of the derivative was proved to
be n for all compact convex domains.
  Tur\'an himself gave comments about the above oscillation question in $L^q$
norm on D. Nevertheless, till recently results were known only for I, D and
so-called R-circular domains.
  Continuing our recent work, also here we investigate the Tur\'an-Er\H{o}d
problem on general classes of domains.
