The Arabic word for Earth is الْأَرْضِ / l-arḍi.
This comes from the root ا ر ﺽ and has the following derivative meanings:
ا ر ﺽ: to rotate; bring forth herbs; that which rotates; earth; land; city; country; ground
As shown above, one of the meanings of this root means to rotate, which is exactly what the Earth does.
Additionally, the Quran in several verses discusses the orbit of the planets.
21:33 And He is the One who created the night and the day, and the sun and the moon; each floating in its own orbit.
وَهُوَ الَّذِي خَلَقَ الَّيْلَ وَالنَّهَارَ وَالشَّمْسَ وَالْقَمَرَ كُلٌّ فِي فَلَكٍ يَسْبَحُونَ
The word for orbit is فَلَكٍ / falakin, this word comes from the root: ف ل ك and has the corresponding derivative meanings:
ف ل ك: to be round; ships; ark; the orbit of a celestial body; pivot; axis
Some people argue that since this is the same root as the word for ship, that this does not mean “orbit” but instead just means to “sail”. What is interesting about this verse and specifically this expression” كُلٌّ فِي فَلَكٍ” which would be translated as “each in orbit” is that this phrase is a palindrome: a phrase that reads the same forward and backward. The significance of this is as if the letters are orbiting around one another like is being described in the verse itself.