Bulk

Bulk is the Zoning Resolution's collective term for the rules controlling a building's size and form — floor area ratio, yards, lot coverage, open space, base and maximum heights, setbacks, and sky exposure planes — as distinct from use rules, which control what activities a building may house. The residence-district bulk rules live in § 23-, with commercial and manufacturing counterparts in § 33- and § 43-.

The use/bulk split is the Resolution's basic grammar: a district assigns both a menu of permitted uses and a bulk regime for the buildings that house them. Most zoning analysis is bulk analysis — how much, how tall, how shaped — because that is where a lot's development capacity is written.