earth: [OE] Earth comes ultimately from an Indo- European base *er-. This produced the prehistoric Germanic noun *erthō, ancestor of German erde, Dutch aarde (whence, via early Afrikaans, English aardvark [19], literally ‘earth-pig’), Swedish and Danish jord, and English earth. Related forms outside Germanic include Greek eraze ‘on the ground’ and Welsh erw ‘field’. The word’s basic range of modern senses, ‘ground’, ‘world’, and ‘soil’, all date back to the Old English period. => aardvark
Old English eorþe "ground, soil, dirt, dry land; country, district," also used (along with middangeard) for "the (material) world, the abode of man" (as opposed to the heavens or the underworld), from Proto-Germanic *ertho (cognates: Old Frisian erthe "earth," Old Saxon ertha, Old Norse jörð, Middle Dutch eerde, Dutch aarde, Old High German erda, German Erde, Gothic airþa), from extended form of PIE root *er- (2) "earth, ground" (cognates: Middle Irish -ert "earth"). The earth considered as a planet was so called from c. 1400. Use in old chemistry is from 1728. Earth-mover "large digging machine" is from 1940.
