A garret is a habitable attic, a living space at the top of a house or larger residential building, often small, dismal, and cramped, with sloping ceilings. In the days before elevators this was the least prestigious position in a building, at the very top of the stairs.

Carl Spitzweg, The Poor Poet (Der arme Poet), 1839, depicting a garret room
Place Saint-Georges in Paris, showing top-floor garret windows