The Collaborative International Dictionary of English v.0.48:

Hayloft \Hay"loft`\ (h[=a]"l[o^]ft`; 115), n.
   A loft or scaffold for hay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

hayloft
    n 1: a loft in a barn where hay is stored [syn: hayloft,
         haymow, mow]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "hayloft":
   attic, attic room, cockloft, crib, elevator, garner, garret,
   grain bin, grain elevator, granary, haymow, hayrick, junk room,
   loft, lumber room, mow, silo, sky parlor, storeroom