Etymology
1. "grass mown," O.E.
heg (Anglian),
hieg, hig (W.Saxon) "grass cut or mown for fodder," from P.Gmc.
*khaujan (cf. O.N.
hey, O.Fris.
ha, M.Du.
hoy, Ger.
Heu, Goth.
hawi "hay"), lit. "that which is cut," or "that which can be mowed," from PIE
*kau- "to hew, strike" (cf. O.E.
heawan "to cut").
Hay-fever is from 1829; earlier it was called
summer catarrh.
Hayseed is from 1577 in the literal sense of "grass seed shaken out of hay;" in U.S. slang sense of "comical rustic" it dates from 1851.
Haymaker in the sense of "very strong blow with the fist" is from 1912, probably in imitation of the wide swinging stroke of a scythe. Slang phrase
hit the hay (pre-1880) was originally "to sleep in a barn;"
hay in the general fig. sense of "bedding" (e.g.
roll in the hay) is from 1903.
2. From Middle English hey, from Old English hīeġ, from Proto-West Germanic *hawi, from Proto-Germanic *hawją, from *hawwaną (“to hew, cut down”).
3. Cognate with West Frisian hea (“hay”), Alemannic German Heuw (“hay”), Cimbrian höobe (“hay”), Dutch hooi (“hay”), German Heu (“hay”), Luxembourgish Hee (“hay”), Mòcheno hei (“hay”), Yiddish היי (hey, “hay”), Danish hø (“hay”), Faroese hoyggj (“hay”), Gutnish hoy (“hay”), Icelandic hey (“hay”), Norwegian Bokmål, Norwegian Nynorsk høy (“hay”), Swedish hö (“hay”), Gothic 𐌷𐌰𐍅𐌹 (hawi, “grass, hay”). More at hew. See: Danish '
hø'.