The vertical elevation of an object above a surface (as sea level or land) of a planet or natural satellite
Distance is a numerical description of how far apart objects are.
"A negative verticalaccuracy signifies that altitude is invalid whereas normally a smaller but positive value of verticalaccuracy actually means that altitude is more precise since it s the vertical distance that it may be off by - i ll leave the discussion as to why this measure is called verticalaccuracy and not verticalinaccuracy for some other time"
from question "When to use sentinel values?"
"Because most of the case zero-altitude distance is quite larger than altitude itself so normally you can ignore altitude"
from question "How to calculate distance between 3 geographic points?"