> btw: why is it named "baseline-skip" and not "baseline-distance"?
This is historical: LilyPond's origins are with TeX, and a 'skip' in TeX is a stretchable and/or compressable whitespace (either horizontal or vertical).[0] The baseline-to-baseline distance is such a skip in TeX; the corresponding variable is called `\baselineskip`. LilyPond took the name, adapting it to its own name conventions, but this distance is no longer stretchable or compressable. Werner [0] I'm omitting more details here for simplicity.