“Semantic web tower”, a product of Tim Berners-Lee’s inspiring drawing on whiteboards. But the most interesting part the “perception” axis is to signify the abstraction/adaptation of the technologies in the tower, towards the people. In fact, this axis could have been well named as the “People axis”, but perception is maybe a more detailed term. In any case, as both perception and people start with P, this can simply be named as the “P” axis.
https://www.w3.org/RDF/Metalog/docs/sw-easy