@item @code{padding} -- the minimum required amount of
unobstructed vertical whitespace between the two items, measured
in staff-spaces.
-@item @code{space} -- the vertical distance, measured in
+@item @code{basic-distance} -- the vertical distance, measured in
staff-spaces, between the reference points of the two items when
no collisions would result, and no stretching or compressing is in
effect.