“Classic six” is one of the most frequently used, yet least understood, terms in the New York real estate lexicon. “Classic” nods to the prewar era when apartments of this ilk were built, and “six” refers to the total number of rooms, which must include a living room, a formal dining room, a kitchen, two full bedrooms, and a maid’s room typically located near the kitchen and with its own bath. These apartments are also home to other architectural touches that were especially popular during that time: hardwood floors, thick walls, spacious rooms, high ceilings, eye-catching moldings, grand entrance galleries, gracious hallways to separate the spaces, and, in some cases, wood-burning fireplaces and private terraces.