Above Ground, On The Ground, The Earth's Surface
noun, の adjective
Remember 地下, which is "below ground." Well, this is ground and above combined together, so I bet you can guess that this means above ground. But usually things above ground don't float (unless you're in space), so it's really on the ground.
ちじょう
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ここは、地上のフロアです。
This is a floor above ground.
ロケットは今、地上三千メートルにいる。
The rocket is now 3,000 meters above the ground.
東京タワーは、地上から見上げると、大きさがよく分かりますね。
You can see the size of the Tokyo Tower if you look up from the ground.