A friend's dictionary says that 'loft' and 'attic' are synonymous.
I think that a loft is the space below the roof, while an attic is a purpose-built room.
Nigel - yes, from Attica. 2 etymology entries from Dictionary.com:
Attic:
1599, "of or pertaining to Attica," from L. Atticus, from Gk. Attikos "of Attica," the region around Athens. Attested from 1563 as an architectural term for a type of column base.
attic:
"top storey under the roof of a house," 1855, shortened from attic storey (1724). The term Attic order in classical architecture meant a small, square decorative column of the type often used in a low storey above a building's main facade, a feature associated with the region around Athens (see Attic). The word then was applied to "a low decorative facade above the main story of a building" (1696), and it came to mean the space enclosed by such a structure. The modern use is via Fr. attique. "An attic is upright, a garret is in a sloping roof"
Loft meanwhile seems to come from the old Norse word "lopt" via Middle English. And to confirm the original suggestion it refers to a room in the attic which is the space below the roof.
Again from the online etymology dictionary:
loft:
"an upper chamber," c.1300, from late O.E. loft "air," from O.N. lopt "air, sky," originally "upper story, loft, attic" (Scand. -pt- pronounced like -ft-), from P.Gmc. *luftuz "air, sky" (cf. O.E. lyft, Du. lucht, O.H.G. luft, Ger. Luft, Goth. luftus "air"). Sense development is from "loft, ceiling" to "sky, air." Buck suggests ult. connection with O.H.G. louft "bark," louba "roof, attic," etc., with development from "bark" to "roof made of bark" to "ceiling," though this did not directly inform the meaning "air, sky." Meaning "gallery in a church" first attested 1504. Verb meaning "to hit a ball high in the air" is first attested 1857, originally in golf. Lofty "exalted" is from 14c.