Is there a term for something like a "routing scheme"?
What your looking for with PCB's is called "block diagrams" basically wrapping up simple functions into a block with the inputs and outputs and showing how they connect to the rest of the functional blocks. e.g. 1 block might be the micro controller and your schematic might group things up to reflect this. e.g. in Kicad hierarchical sheets can be used to make schematics that look exactly like block diagrams. 

Attached below is one such block diagram from one of the projects I have worked on in the past, there are nicer ways of doing this, for me it was just to break up different areas so multiple sheets could be worked by different people at the same time.