(1):

(a.) A room or rooms behind that part of the exterior; all the rooms immediately below the roof.

(2):

(a.) 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.

(3):

(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:

(4):

(a.) An Athenian; an Athenian author.