What is the meaning of attic in one word?

The meaning of attic in one word is loft or garret, both are synonyms that capture essence of attic as uppermost storage space under roof. If you need single word definition, attic is essentially storage space, but closest one word synonym is garret, which specifically means habitable attic or small room at top of house. Another one word meaning is loft, which is commonly used in British English to mean attic space under roof. In architectural terms, attic can be defined as crawlspace if unfinished, but garret is most precise one word equivalent for finished attic room. If you want descriptive one word meaning rather than synonym, attic means upper room, but garret is accepted one word dictionary synonym. So answer in one word could be loft, garret, or storage, with garret being most traditional literary synonym for attic space used for living or storage under roof.