3-Way Driver Spacing

I have a quick question in regards to the distance between speakers. I have read that the vertical distance is a relation to the wavelength of the highest freq., I assume this is the crossover freq.?? Is this distance from center to center of the speaker?

In a TMW 3-Way, would the spacing between the woofer and the midrange be the lower crossover freq. and the spacing between the midrange and the tweeter be the upper crossover freq.?