(Dutch for 'building plan') a Cathedral growth model. Every building plan has at least two 'attraction poles'  and all Cathedral growth is situated in between these poles. An attraction pole also functions as a gateway to the outside of a Cathedral. In the Cathedral web app environment this model translates to a 'navigation menu' like we know it from early web-days. As the net evolves, losing its superfluous metaphors, this will evolve more to a GUI to the global database that is in fact the internet.
In the first few years the growth model was based on the four wind directions. This was done to reassure users who were at that time largely indoctrinated by the omnipresent 'Where shall we go today?'  metaphorical BS from Microsoft. People were 'going on the internet' and 'visiting' 'websites'! Of course people were just sitting in front of a screen pouring tons of light over them so their eyesight got its due part in the generally deteriorating state of things healthwise...

The first Cathedral Bouwplan also had a central square called the 'Meret Becker Plaza'. Meret Becker is a ridiculously cool and pretty German singer and actress who is obnoxiously refusing to marry the current Cathedral Author.
Plans for the second Cathedral Bouwplan have been published on January 5th 2017. Not much is presently known about them, but they include 'a colored categorical scheme of human emotions' and 'seven main suctions' (dv in a Facebook Anouncement he was about to make at the time of writing this Lexicon Lemma).