Origin and history of sward

"grass-covered ground, grassy surface of land," c. 1300, "turf, sod," a specialized use from Old English sweard "skin, hide, rind" (of bacon, etc.), from Proto-Germanic *swardo- (source also of Old Frisian swarde "skin of the head," Middle Dutch swarde "rind of bacon," Dutch zwoord "rind of bacon," German Schwarte "thick, hard skin, rind," Old Norse svörþr "walrus hide"). Boutkan gives it no IE etymology and calls it "Probably a Northern European substratum word."

The meaning "sod, turf" developed from the notion of the "skin" of the earth (compare Old Norse grassvörðr, Danish grønsvær "greensward").