Openstreetmap is map data that is basically coordinates with tags on them and relations between those tags. I guess this is true for most GIS software but there is very little 2D map data that can not be described in the OSM tagging model.

You can never express everything with tags, you need stats and metadata on metadata, documentation and a strong heterogeneity which also need to be able to adapt to new ideas.

https://wiki.openstreetmap.org/wiki/Tags https://wiki.openstreetmap.org/wiki/Map_features