c. 1300, originally "land, area, place," from Anglo-French soil "piece of ground, place" (13c.), from a merger or confusion of Old French sol "bottom, ground, soil" (12c., from Latin solum "soil, ground;" see sole (n.1)), Old French soeul, sueil "threshold, area, place" (from Latin solium "seat," from PIE *sodio- "seat," from PIE root *sed- (1) "to sit"), and Old French soil, soille "a miry place," from soillier (see soil (v.)).
Meaning "place of one's nativity" is from c. 1400. Meaning "mould, earth, dirt" (especially that which plants grow in) is attested from mid-15c.