From PIE *h1er- (ground) — the only planet not named after a god. We simply called our world 'the ground.'
The planet on which we live; the substance of the land surface; soil.
From Old English "eorþe" (ground, soil, the world), from Proto-Germanic *erþō (earth, ground), from PIE *h₁er- (earth, ground). This is one of the oldest and most stable words in the Germanic vocabulary, with cognates in every Germanic language: German "Erde," Dutch "aarde," Old Norse "jǫrð" (→ Icelandic "jörð"), Gothic "airþa," Swedish "jord." The PIE root *h₁er- also appears outside Germanic: Greek "ἔρα" (éra, earth), and possibly Welsh "erw" (field, acre). The word has three distinct but related