attic:  In classical architecture, an Attic order was a pilaster, or square column (the naḿe comes from Attica, a region of ancient Greece of which Athens was the capital). This type of column was often used in a relatively low storey placed above the much higher main façade of a building, which hence became known in the 18th century as an attic storey. It was a short step to applying the word attic itself to an ‘upper storey’; the first record of it in this sense comes in Byron’s Beppo 1817: ‘His wife would mount, at times, her highest attic’.
1590s, "pertaining to Attica," from Latin Atticus, from Greek Attikos "Athenian, of Attica," the region around Athens (see Attica). Attested from 1560s as an architectural term for a type of column base.
"top story 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 story above a building's main facade, a feature associated with the region around Athens (see Attic). The word then was applied by architects to "a low decorative facade above the main story of a building" (1690s in English) to convey a classical heritage where none exists, and it came to mean the space enclosed by such a structure. The modern use is via French attique. "An attic is upright, a garret is in a sloping roof" [Weekley].