NYC Real Estate Glossary
138 terms covering every abbreviation, acronym, and concept you will encounter in NYC property transactions — explained in plain English.
From agency acronyms (DOB, HPD, ECB) to zoning districts (R1-R10, C1-C8, M1-M3), tax classes, title terms, violation types, and construction permits. Bookmark this page as your reference guide.
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421-a
A NYC tax exemption program for new residential construction providing a 15-35 year phase-in of full property taxes. Expired in 2022 and replaced by 485-x in 2024. When benefits expire, property taxes can increase dramatically. Learn more
485-x
The successor to the 421-a tax exemption program for new residential construction. Requires affordable housing units and prevailing wage for construction workers.
80/20 Building
A building where 80% of units are market-rate and 20% are affordable, built under a tax incentive program. The affordable units have income restrictions.
A
ACRIS
Automated City Register Information System — NYC's online portal for recording and searching property documents including deeds, mortgages, and liens. Maintained by the Department of Finance with records dating back to 1966. Learn more
AHV
After Hours Variance — a DOB permit allowing construction work outside normal hours (typically before 7 AM or after 6 PM weekdays, or weekends). Required for non-emergency after-hours work.
Air Rights
The unused development rights above an existing building. If a building uses only 10,000 sq ft of a permitted 20,000 sq ft FAR, it has 10,000 sq ft of unused air rights that can potentially be transferred. Learn more
ALT1
Alteration Type 1 — a major alteration that changes the building's use, egress, or occupancy. Requires a new Certificate of Occupancy.
ALT2
Alteration Type 2 — multiple types of work that do not change the building's use, egress, or occupancy. Examples include new plumbing, HVAC, and structural changes.
ALT3
Alteration Type 3 — one type of minor work such as replacing a boiler, installing a curb cut, or adding a fire escape.
Article 7-A
A provision allowing tenants in buildings with serious code violations to petition for appointment of an administrator to manage the building and make repairs using collected rents.
Asbestos
A building material used extensively before 1980 for insulation and fireproofing. Must be tested and professionally abated before renovation or demolition. DEP regulates asbestos removal in NYC.
Assessed Value
The value assigned to a property by DOF for tax purposes. Not the same as market value. The ratio of assessed value to market value depends on the tax class.
B
Bargain and Sale Deed
The most common deed type in NYC. Implies the grantor has title but provides limited warranties. May include covenants against grantor's acts.
BBL
Borough-Block-Lot — the universal property identifier in NYC. A 10-digit number: 1 digit for borough (1=Manhattan, 2=Bronx, 3=Brooklyn, 4=Queens, 5=Staten Island), 5 digits for block, and 4 digits for lot. Example: 1007350001 = Manhattan, Block 735, Lot 1. Learn more
BIN
Building Identification Number — a 7-digit number identifying a specific building. First digit equals the borough code. A single lot (BBL) can have multiple BINs if it contains multiple buildings. Learn more
BIS
Building Information System — DOB's legacy database for looking up building permits, violations, complaints, and Certificates of Occupancy.
Block
A tax block — a group of contiguous tax lots bounded by streets. Part of the BBL identifier. Blocks are numbered within each borough.
Brownfield
A property where development or reuse is complicated by the presence or potential presence of contamination. NYC and NYS offer tax incentives for brownfield cleanup and redevelopment.
BSA
Board of Standards and Appeals — grants variances and special permits for properties that cannot comply with zoning regulations. Appeals of DOB determinations go here.
Building Class
A DOF classification code indicating the type and use of a building. Examples: A0 (Cape Cod), C0 (walk-up), D4 (elevator coop), O4 (office tower), S1 (warehouse).
Building Permit
Authorization from DOB to perform construction work. Required for new buildings, alterations, demolitions, and certain equipment installations. Work without a permit is a violation. Learn more
C
C of O
Certificate of Occupancy — the DOB document defining how a building can legally be used (residential, commercial, mixed-use) and how many units or occupants it can have. Mismatches between actual use and C of O are illegal conversions. Learn more
C1 through C8
Commercial zoning districts. C1-C2 are local retail; C3 is waterfront recreation; C4 is regional commercial (malls); C5-C6 are central commercial (office towers); C7 is amusement; C8 is heavy commercial/automotive.
Cap Rate
Capitalization Rate — the ratio of net operating income to property value. Used to evaluate investment properties. A 5% cap rate means the property generates 5% of its value in annual net income.
Certiorari
A legal proceeding to challenge a property tax assessment. Filed with the NYC Tax Commission (administrative) or Supreme Court (Article 7). A multi-billion dollar industry in NYC.
Chain of Title
The complete history of ownership transfers for a property from the original grant to the current owner. Gaps or irregularities in the chain can create title defects.
Class 1 Violation (DOB)
A DOB violation indicating a condition that poses an immediate threat to public safety. Requires immediate correction. Learn more
Class 2 Violation (DOB)
A DOB violation for a major condition that must be corrected within a specified timeframe. Learn more
Class 3 Violation (DOB)
A DOB violation for a lesser condition that does not pose an immediate safety risk but must be corrected. Learn more
Class A Violation (HPD)
Non-hazardous violation — minor maintenance issues like small cracks, peeling paint in non-lead areas. Landlord has 90 days to correct. Learn more
Class B Violation (HPD)
Hazardous violation — conditions dangerous to health or safety such as water leaks, broken locks, inadequate lighting. Landlord has 30 days to correct. Learn more
Class C Violation (HPD)
Immediately hazardous violation — conditions posing immediate risk to life or safety including lead paint in units with children under 6, no heat or hot water, and severe rodent infestations (routine pest conditions are Class B). Landlord has 24 hours to correct. Learn more
Closing Costs
Expenses beyond the purchase price paid at closing. In NYC, these include transfer taxes, mansion tax, title insurance, attorney fees, mortgage recording tax, and (for co-ops) flip tax.
Co-op
Cooperative — a form of ownership where a corporation owns the building and residents own shares in the corporation plus a proprietary lease. Co-op sales require board approval and shares cannot be directly mortgaged (financing uses a stock pledge).
Commercial Property
Property used for business purposes including office buildings, retail stores, warehouses, and hotels. Classified as Tax Class 4 in NYC.
Condo
Condominium — a form of ownership where individual units are owned outright and common areas are shared. Each unit has its own BBL and tax bill. Condos can be freely mortgaged and sold.
Condo Declaration
The legal document that creates a condominium, filed with the county clerk. Defines individual units, common elements, and the rules governing the condominium.
Contextual Zoning
Zoning regulations that require new buildings to match the existing neighborhood context in terms of height, setback, and street wall. Indicated by a letter suffix (e.g., R7A, R8B).
D
DCP
Department of City Planning — sets zoning regulations, manages ULURP, and maintains ZoLa (Zoning and Land Use Map). Learn more
DCWP
Department of Consumer and Worker Protection (formerly DCA) — licenses and regulates businesses in NYC.
Deed
A legal document that transfers ownership of real property from one party to another. Recorded in ACRIS. Common types include bargain and sale deed, quitclaim deed, and referee's deed. Learn more
DEP
Department of Environmental Protection — manages NYC's water supply and sewer system. Unpaid DEP bills become senior liens on the property.
DHE
Disabled Homeowner Exemption — similar to SCHE but for homeowners with disabilities. Provides a 5-50% reduction in assessed value based on income.
DM
Demolition — a DOB permit type for the complete or partial demolition of a building.
DOB
Department of Buildings — issues building permits, inspects construction, issues Certificates of Occupancy, and tracks violations. The primary construction regulatory agency in NYC. Learn more
DOB NOW
DOB's newer online filing system gradually replacing the legacy BIS system. Used for certain permit types, inspections, and violations.
DOF
Department of Finance — assesses property values, collects property taxes, maintains ACRIS, and manages tax liens. Learn more
DSNY
Department of Sanitation — enforces recycling and waste disposal rules. Can issue ECB violations for non-compliance.
Due Diligence
The comprehensive investigation of a property before purchase. In NYC, this includes title search, violation check, permit history, tax analysis, zoning review, and environmental assessment. Learn more
E
E-Designation
An environmental restriction placed on a property through the zoning process requiring environmental review and remediation before development can proceed.
Easement
A right to use another person's land for a specific purpose, such as a utility company's right to run power lines across a property. Runs with the land and transfers with ownership.
ECB
Environmental Control Board (now part of OATH) — adjudicates violations from DOB, FDNY, DEP, DSNY, and other agencies. Unpaid ECB fines become liens on the property.
ECB Default
When a respondent fails to appear for an ECB hearing or pay a fine, a default judgment is entered. Default penalties are typically the maximum amount and become liens on the property. Learn more
Encumbrance
Any claim, lien, charge, or liability attached to real property. Includes mortgages, liens, easements, restrictions, and encroachments.
F
FAR
Floor Area Ratio — the ratio of a building's total floor area to the size of its lot. FAR 2.0 on a 10,000 sq ft lot means a maximum of 20,000 sq ft of building. The key metric for development potential. Learn more
FDNY
Fire Department of New York — enforces fire safety codes, inspects sprinkler and standpipe systems, and issues violations for non-compliance.
FISP
Facade Inspection and Safety Program (formerly Local Law 11) — requires buildings over 6 stories to inspect exterior walls and appurtenances every 5 years. Conditions are classified as Safe, SWARMP, or Unsafe.
Flip Tax
A fee charged by co-op buildings on the sale of shares, typically 1-3% of the sale price. Paid by the seller to the co-op corporation. Not a government tax.
G
GRM
Gross Rent Multiplier — the ratio of a property's price to its gross annual rental income. A quick way to compare investment properties. Lower GRM generally indicates better value.
H
HDFC
Housing Development Fund Corporation — a type of co-op with income restrictions, originally created through city programs to provide affordable homeownership. Often converted from formerly city-owned buildings.
Housing Court
Part of NYC Civil Court that handles landlord-tenant disputes including non-payment proceedings, holdover proceedings, and HP actions (tenant-initiated repair cases).
HPD
Housing Preservation & Development — enforces the Housing Maintenance Code for residential buildings. Issues violations for habitability issues like heat, lead paint, pests, and mold. Learn more
HPD Registration
All buildings with 3 or more residential units must register annually with HPD. Non-registration can result in penalties and bars owners from certifying violations as corrected.
I
ICAP
Industrial and Commercial Abatement Program — a tax abatement for commercial and industrial property renovations in NYC.
Illegal Conversion
Using a building or space in a manner inconsistent with the Certificate of Occupancy, such as converting a basement into an apartment without permits. A serious violation that can trigger vacate orders.
Immediately Hazardous
A DOB violation classification for conditions that pose an immediate threat to public safety, requiring the owner to take corrective action within 24 hours or face vacate orders.
Inclusionary Housing
A zoning program that provides a FAR bonus in exchange for including affordable housing units. Mandatory Inclusionary Housing (MIH) was adopted in 2016 for new rezonings.
Industrial Property
Property used for manufacturing, warehousing, or distribution. Typically in M-zoned districts. Subject to Industrial Business Zone (IBZ) protections in some areas.
J
J-51
A NYC tax exemption and abatement program for residential building rehabilitation. Provides both a reduced assessed value and direct tax reduction. Expiration can cause tax jumps of 200-400%. Learn more
L
Landmark
A building, site, or district designated by the Landmarks Preservation Commission as having special historical, cultural, or architectural significance. Exterior alterations require LPC approval. Learn more
Lead Paint
Paint containing lead, banned in 1978. In NYC, Local Law 1 requires landlords to remediate lead paint in apartments with children under 6. Lead violations are Class C (immediately hazardous).
Letter of Completion
A DOB document issued when an alteration is complete and compliant, signed off by all required inspections. Required to close out a permit.
Lien
A legal claim on property as security for a debt. Can be voluntary (mortgage) or involuntary (tax lien, judgment lien, mechanic's lien). Liens must be cleared before a clean title transfer. Learn more
Lis Pendens
A public notice filed in court records indicating a pending lawsuit affecting a property. Title companies flag lis pendens as they may affect ownership or create encumbrances.
LL84
Local Law 84 — requires buildings over 25,000 sq ft to benchmark energy and water usage annually. Data is publicly available.
LL87
Local Law 87 — requires buildings over 50,000 sq ft to conduct energy audits and retro-commissioning every 10 years.
LL97
Local Law 97 (Climate Mobilization Act) — NYC's landmark emissions law setting carbon caps for buildings over 25,000 sq ft, with fines of $268 per ton over the limit. Caps tighten in 2030. Learn more
Lot
A tax lot — the smallest unit of real property in NYC. Identified by a 4-digit number within a block. A lot can contain one or more buildings.
LPC
Landmarks Preservation Commission — designates and regulates landmarks and historic districts. Work on landmarked buildings requires LPC approval before DOB permits.
M
M1 through M3
Manufacturing zoning districts. M1 is light manufacturing (often compatible with commercial uses); M2 is medium manufacturing; M3 is heavy manufacturing. M1 districts are frequently rezoned for mixed-use development.
Mansion Tax
A NYS transfer tax on residential purchases of $1 million or more. Ranges from 1% at $1M to 3.9% for purchases of $25M or more. Paid by the buyer.
Market Value
DOF's estimate of what a property would sell for in the open market. Used as the starting point to calculate assessed value. Often differs from actual sale prices.
MDR
Multiple Dwelling Registration — the HPD registration for buildings with 3 or more residential units. Provides contact information for the building owner or managing agent.
Mechanic's Lien
A lien filed by a contractor, subcontractor, or supplier who performed work on a property but was not paid. Must be filed within 8 months of last work in NYC (4 months for single-family homes).
Mitchell-Lama
A NYS housing program from 1955 providing middle-income housing with below-market rents. Buildings can exit the program after paying off their mortgage, potentially converting to market rate.
Mixed-Use
A building containing both residential and commercial uses, typically with retail or offices on lower floors and apartments above. Common in NYC, especially along commercial corridors.
Mortgage
A loan secured by real property. The mortgage document is recorded in ACRIS and creates a lien on the property until the loan is paid off or satisfied.
Mortgage Recording Tax
A tax paid when recording a new mortgage in NYC. 1.8% for mortgages under $500K, 1.925% for $500K and above. Split between borrower and lender.
N
NB
New Building — a DOB permit type for construction of a brand new building, as opposed to Alteration (ALT) or Demolition (DM).
NOI
Net Operating Income — a property's annual income after operating expenses but before debt service and capital expenditures. The key metric for valuing income-producing real estate.
NOPV
Notice of Property Value — the annual letter from DOF informing property owners of their new assessed value. Mailed in January. The basis for property tax appeals with a March deadline.
NYC Open Data
The city's open data portal (data.cityofnewyork.us) providing free public access to datasets from city agencies. RegWatch aggregates and normalizes data from this and other city sources.
O
OATH
Office of Administrative Trials and Hearings — adjudicates city agency violations. Replaced ECB as the hearing body where DOB, HPD, and FDNY violations are heard and fines imposed.
OER
Office of Environmental Remediation — oversees cleanup of contaminated properties through the NYC Voluntary Cleanup Program (VCP) and NYC Brownfield Cleanup Program (BCP).
Offering Plan
A document filed with the NY Attorney General's office when a building is first offered for sale as a condo or co-op. Contains building details, financial projections, and terms of sale.
Overlay District
A zoning designation layered on top of an existing district that modifies certain rules. Examples include Commercial Overlays (C1-1, C2-1) on residential districts that allow ground-floor retail.
P
Phase I ESA
Phase I Environmental Site Assessment — a study of a property's environmental condition based on historical records, site inspection, and interviews. Required for most commercial transactions to establish innocent landowner defense.
Phase II ESA
Phase II Environmental Site Assessment — involves actual sampling and testing of soil, groundwater, or building materials. Conducted when Phase I identifies potential contamination.
PLUTO
Primary Land Use Tax Lot Output — NYC Planning's comprehensive dataset of every tax lot in NYC including owner, zoning, FAR, assessed value, building class, lot size, and more. Available via NYC Open Data.
Professional Certification
A process where a licensed architect or engineer certifies that work complies with code, bypassing DOB plan review. Faster but the professional assumes liability.
Q
Quitclaim Deed
A deed that transfers whatever interest the grantor has in the property without any warranty or guarantee of clear title. Common in transfers between family members or to clear title defects.
R
R1 through R10
Residential zoning districts in NYC, ranging from R1 (single-family detached, lowest density) to R10 (high-rise apartment buildings, highest density). Each district has specific FAR, lot coverage, height, and setback requirements.
Rent Control
The older, more restrictive rent regulation system. Covers tenants who have continuously occupied their apartment since before July 1, 1971 in buildings built before 1947. Fewer than 22,000 units remain.
Rent Stabilization
A NYC rent regulation system covering approximately 1 million apartments. Limits annual rent increases to percentages set by the Rent Guidelines Board. Buildings with 6+ units built before 1974 are generally covered. Learn more
RPIE
Real Property Income & Expense — an annual filing required by DOF for income-producing properties. Reports actual income and expenses. Non-filing means DOF can deny your tax certiorari challenge. Filing deadline is September 1.
S
Satisfaction of Mortgage
A document recorded when a mortgage is fully paid off, releasing the lien on the property. Should be recorded in ACRIS within 30 days of payoff.
SCA
School Construction Authority — manages construction and renovation of NYC public school buildings.
Scaffold
In NYC, buildings taller than 6 stories must undergo facade inspections every 5 years (FISP/Local Law 11). Unsafe facades require scaffolding (sidewalk sheds) which can remain for years.
SCHE
Senior Citizen Homeowner Exemption — reduces assessed value by 5-50% based on income for homeowners 65 and older.
Special District
A zoning area with unique rules tailored to specific neighborhood goals. Examples: Special Midtown District, Special Hudson Yards District, Special Little Italy District. Rules override or supplement underlying zoning.
Special Permit
A discretionary approval from City Planning or BSA for uses or bulk modifications that are permitted in a zoning district but require additional review. Less strict than a variance.
STAR
School Tax Relief — reduces the school tax portion of property taxes for primary residences. Basic STAR for all qualifying homeowners; Enhanced STAR for seniors 65+ with income limits.
SWO
Stop Work Order — a DOB order halting all construction work at a site. Issued for safety violations, work without permits, or other serious non-compliance. Fines accumulate daily until resolved. Learn more
T
Tax Abatement
A direct reduction in the amount of property tax owed, applied after the tax rate is calculated. Different from an exemption, which reduces assessed value.
Tax Class 1
Small residential properties: 1-3 family homes, small condos. Assessed at 6% of market value. Subject to assessment increase caps (6% per year, 20% over 5 years). Learn more
Tax Class 2
Larger residential properties: apartment buildings with 4+ units, co-ops, and condos. Assessed at 45% of market value. Subject to assessment increase caps (8% per year, 30% over 5 years).
Tax Class 3
Utility company equipment and special franchise properties. Assessed at varying rates.
Tax Class 4
All commercial and industrial properties including offices, retail, hotels, and factories. Assessed at 45% of market value. No assessment increase caps.
Tax Exemption
A reduction in the assessed value of a property for tax purposes. Examples include 421-a (new construction), J-51 (rehabilitation), SCHE (senior citizens), and veterans exemptions.
Tax Lien Sale
NYC sells liens on properties with delinquent taxes, water charges, or other municipal debts. Liens are sold to a trust that can foreclose. Properties enter the sale after one year of delinquency. Learn more
Tax Map
An official map maintained by DOF showing the boundaries of every tax lot in NYC. Used to determine property boundaries, block and lot numbers, and lot dimensions.
TCO
Temporary Certificate of Occupancy — allows partial occupancy while construction continues. Must be renewed periodically (typically every 90 days) until a permanent C of O is issued.
TDR
Transfer of Development Rights — the sale or transfer of unused air rights from one property to another. In NYC, transfers are generally limited to adjacent lots or within special districts.
Title Abstract
A summary of all documents recorded against a property, organized chronologically. Shows the chain of ownership, mortgages, liens, and encumbrances. Not the same as title insurance. Learn more
Title Insurance
An insurance policy protecting the buyer or lender against losses from defects in the title. In NYC, title insurance is standard for purchases and required for most mortgages.
Townhouse
A single-family attached or semi-detached row house, typically 3-5 stories. In NYC, often classified as a Class 1 property for tax purposes.
Transfer Tax
Taxes paid when property changes hands. NYC imposes a Real Property Transfer Tax (RPTT) of 1-2.625% depending on price and property type. NYS imposes an additional transfer tax plus mansion tax for sales over $1M.
U
UCC Filing
Uniform Commercial Code filing — a public record of a security interest in personal property or fixtures. UCC-1 filings on co-op shares serve as the equivalent of a mortgage.
ULURP
Uniform Land Use Review Procedure — the public review process for proposed land use changes in NYC. Required for rezonings, special permits, and other major actions. Takes approximately 7 months. Learn more
Use Group
NYC zoning organizes permitted activities into 18 Use Groups (UG 1 through UG 18). UG 1-2 are residential, UG 3-4 are community facilities, UG 5-14 are commercial, and UG 15-18 are manufacturing.
V
Vacant Lot
An empty parcel of land with no buildings. Development potential is determined by the zoning district's permitted uses, FAR, and other bulk regulations.
Vacate Order
An order requiring occupants to leave a building or portion of a building due to unsafe conditions. Issued by DOB and can be partial or full.
Variance
A discretionary approval from the BSA allowing a property to deviate from zoning regulations. Requires proving that strict compliance would create unnecessary hardship due to unique physical conditions of the lot.
W
Walk-up
A residential building without an elevator, typically 5-6 stories or fewer. Buildings with 6+ stories generally require elevators under NYC building code.
Waterfront Zoning
Special rules for properties along NYC's waterfront requiring public access areas (Waterfront Access Plan), visual corridors, and restrictions on building placement.
Z
ZoLa
Zoning and Land Use Application — DCP's online interactive map for looking up zoning information for any property in NYC. Learn more
Zoning Lot
A tract of land comprising a single tax lot or a group of adjacent tax lots assembled for development purposes. A zoning lot may differ from a tax lot. Learn more
Zoning Map
The official map showing zoning district boundaries for all of NYC. Maintained by DCP and available online through ZoLa (Zoning and Land Use Application).
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