What is a freestanding mountain?

The sign on the top of Uhuru Peak (Mt. Kilimanjaro) proclaims it to be the world's highest "free-standing mountain." Probably a bit of a misnomer, intended to mean that it is the world's highest mountain from base to peak.

No, not really. A "Free-standing" mountain is a mountain on sea level, meaning it is not in a mountain range. For example, Mt. Everest is in the Himalayas mountain range. Meaning it is surrounded by very close mountains, which means its base is at an extremely high 2,000-4,000 m (meters) , then starting towards 8,002 m.