"grass mown," Old English heg (Anglian), hieg, hig (West Saxon) "grass cut or mown for fodder," from Proto-Germanic *haujam (source also of Old Norse hey, Old Frisian ha, Middle Dutch hoy, German Heu, Gothic hawi "hay"), literally "that which is cut," or "that which can be mowed" (from PIE *kau- "to hew, strike;" source also of Old English heawan "to cut;" see hew).
Slang phrase hit the hay (pre-1880) was originally "to sleep in a barn;" hay in the general figurative sense of "bedding" is from 1903; roll in the hay (n.) is from 1941.
"large bundle or package of merchandise prepared for transportation," early 14c., from Old French bale "rolled-up bundle" (13c., Modern French balle), from Frankish or some other Germanic source (such as Old High German balla "ball"), from Proto-Germanic *ball- (from PIE root *bhel- (2) "to blow, swell"). The English word perhaps is via Flemish or Dutch, which got it from French.
also hay-fever, 1825, from hay + fever. Also called summer catarrh (1828); not much noted before the 1820s, when it was sometimes derided as a "fashion" in disease.
People are apt to sneeze, in hot weather for example; and people do not die of sneezing now-a-days, as they did in days that no one knows any thing about. We cannot give six draughts a-day, at one and nine pence each, for sneezing: call it the hay-fever. What a wonderful man! what a clever man! he understands the hay-fever: call him in! Thus is the hay-fever among the last in the list of fashionables. ["On Fashions in Physic," London Magazine, October 1825]
machine that makes bales, 1888, agent noun from bale (v.).
"stack of hay," Old English muga, muwa "a heap (of grain, pease, etc.), swath of corn; crowd of people," earlier muha, from Proto-Germanic *mugon (source also of Old Norse mugr "a heap," mostr "crowd"), of uncertain origin. Meaning "place in a barn where hay or sheaves of grain are stored" is by 1755.