The Collaborative International Dictionary of English v.0.48:

Attic \At"tic\, a. [L. Atticus, Gr. ?.]
   Of or pertaining to Attica, in Greece, or to Athens, its
   principal city; marked by such qualities as were
   characteristic of the Athenians; classical; refined.
   [1913 Webster]

   Attic base (Arch.), a peculiar form of molded base for a
      column or pilaster, described by Vitruvius, applied under
      the Roman Empire to the Ionic and Corinthian and "Roman
      Doric" orders, and imitated by the architects of the
      Renaissance.

   Attic faith, inviolable faith.

   Attic purity, special purity of language.

   Attic salt, Attic wit, a poignant, delicate wit, peculiar
      to the Athenians.

   Attic story. See Attic, n.

   Attic style, a style pure and elegant.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Attic \At"tic\, n. [In sense (a) from F. attique, orig. meaning
   Attic. See Attic, a.]
   1. (Arch.)
      (a) A low story above the main order or orders of a
          facade, in the classical styles; -- a term introduced
          in the 17th century. Hence:
      (b) A room or rooms behind that part of the exterior; all
          the rooms immediately below the roof.
          [1913 Webster]

   2. An Athenian; an Athenian author.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Attic
    adj 1: of or relating to Attica or its inhabitants or to the
           dialect spoken in Athens in classical times; "Attic
           Greek"
    n 1: floor consisting of open space at the top of a house just
         below roof; often used for storage [syn: loft, attic,
         garret]
    2: the dialect of Ancient Greek spoken and written in Attica and
       Athens and Ionia [syn: Attic, Ionic, Ionic dialect,
       Classical Greek]
    3: informal terms for a human head [syn: attic, bean,
       bonce, noodle, noggin, dome]
    4: (architecture) a low wall at the top of the entablature;
       hides the roof

Moby Thesaurus II by Grady Ward, 1.0:

66 Moby Thesaurus words for "attic":
   archives, armory, arsenal, attic room, bank, basement, bay, bin,
   bonded warehouse, bookcase, box, bunker, buttery, cargo dock,
   cellar, chest, closet, cockloft, conservatory, crate, crib,
   cupboard, depository, depot, dock, drawer, dump, exchequer, garret,
   glory hole, godown, hayloft, hold, hutch, junk room, library,
   locker, loft, lumber room, lumberyard, magasin, magazine, rack,
   repertory, repository, reservoir, rick, shelf, sky parlor, stack,
   stack room, stock room, storage, store, storehouse, storeroom,
   supply base, supply depot, tank, treasure house, treasure room,
   treasury, vat, vault, warehouse, wine cellar



Moby Thesaurus II by Grady Ward, 1.0:

90 Moby Thesaurus words for "Attic":
   Ciceronian, aesthetic, artistic, biting, brilliant, chaste, choice,
   classic, classical, clear, clever, common, commonplace, direct,
   droll, easy, elegant, everyday, excellent, facetious, finished,
   funny, garden, garden-variety, graceful, gracile, homely, homespun,
   household, humorous, humorsome, in good taste, jesting, jocose,
   jocular, joking, joky, joshing, keen, keen-witted, limpid, lucid,
   matter-of-fact, mordant, natural, neat, nimble-witted, nondescript,
   of choice, of quality, ordinary, pellucid, perspicuous, plain,
   pleasing, pointed, polished, prosaic, prosy, pungent, pure,
   pure and simple, quick-witted, quiet, rapier-like, refined,
   restrained, round, salt, salty, scintillating, sharp, simple,
   smart, sparkling, sprightly, straightforward, subdued, tasteful,
   terse, trim, unaffected, understated, unlabored, unobtrusive,
   well-chosen, whimsical, witty, workaday, workday