Reference glossary
A field guide to reading your street
Keep this page open on your phone during a walk. Terms are grouped by what they govern: land, form, movement, and change over time. Each entry is written to be understood without a planning degree.
Land & Regulation
- Setback
- The minimum distance a building must be placed from a property line, most commonly the front line facing the street. Setback rules explain why some blocks have deep front yards and others have none at all.
- Floor Area Ratio (FAR)
- A ratio between a building's total floor area and the size of its lot. A high FAR allows a taller or bulkier building relative to lot size; a low FAR keeps buildings comparatively low and spread out.
- Overlay district
- An additional set of rules layered on top of standard zoning for a specific area, often used to protect a historic character or manage a particular corridor without rewriting the base zoning entirely.
- Variance
- A formally granted exception to a specific zoning rule for one property, usually approved after a hearing where a property owner demonstrates a rule would create unreasonable hardship.
Form & Facade
- Cornice line
- The horizontal projection near the top of a building's facade. Matching cornice heights along a block are often the result of an old ordinance rather than coordinated taste among separate owners.
- Party wall
- A shared wall between two attached buildings, typically load-bearing for both sides. Party wall construction is the structural reason rowhouses can be built so close together without individual side walls.
- Fenestration
- The arrangement of windows on a facade. Regular, evenly spaced fenestration is often a marker of a specific construction period tied to standardized window sizes and structural grids.
- String course
- A horizontal band, often of contrasting material, running across a facade to mark a floor division. Useful as a quick visual cue for counting stories on older masonry buildings.
Movement & Infrastructure
Two terms that explain most of what changed once cities began designing around vehicles rather than pedestrians.
Arterial road
A road designed to carry higher traffic volumes between districts rather than serve local access. Arterial planning frequently required widening or straightening streets, which meant demolishing existing buildings along their path.
Superblock
A large development parcel formed by closing or removing several original city blocks and their internal streets. Superblocks were common in mid-century renewal projects and often replaced a fine street grid with a single large footprint.
Cul-de-sac
A street closed at one end, typically used in postwar residential subdivisions to limit through traffic. Its spread coincided with a shift away from the continuous grid layouts common in older neighborhoods.
Historic district
A formally designated area where exterior alterations to buildings are reviewed against preservation guidelines, usually to maintain a recognized architectural character established during a specific historical period.
Preservation & Change
- Adaptive reuse
- Converting a building to a new function, most commonly turning former industrial or commercial buildings into residential or mixed-use space, while retaining much of the original structure and exterior.
- Infill development
- New construction placed on a vacant or underused lot within an already built-up area, rather than expanding outward into undeveloped land.
- Demolition by neglect
- The gradual deterioration of a building through lack of maintenance until it becomes unsafe to preserve, sometimes used, deliberately or not, as an alternative to a formal demolition request that would otherwise require review.
- Facadism
- A development approach that preserves only the street-facing wall of an older building while replacing everything behind it with new construction, often to satisfy preservation review while maximizing new interior space.