[Dolphinsiu]

H = L(length of column)/N(no of theoretical plates) is known as another measure for column efficiency.

My notes says that it has physical meaning: distance required for partition equilibrium, K = Cs/CM  (Craig's transfer process).

What is meant by 'distance required for partition equilibrium'?
distance means
(i) 'length of time for elution' or
(ii) 'diffusion distance either from stationary phase to mobile phase or mobile phase to stationary phase' or
(iii) 'eluting distance from the top to the bottom of column'?

Only the word 'distance' make me quite confused.