Affordable Housing - Housing that costs no more than 30 percent of a household's income on rent or mortgage payments. This percentage meets the federal guideline for affordability.*Some states include the cost of utilities in the 30 percent calculation; Delaware does include the cost of utilities.

Accessory Dwelling Unit - A self-contained living unit either attached to or detached from, and in addition to, the primary residential unit on a single lot. Sometimes called "granny flat" or "second unit".

Area Median Income (AMI) - HUD uses the median income to calculate income limits for eligibility in a variety of housing programs. The median divides the income distribution into two equal parts: one-half of the cases falling below the median income and one-half above the median.

Below-Market Rate (BMR) - Any housing unit intentionally priced less than fair-market value, to be sold or rented to the low- and moderate-income market.

Community Land Trusts (CLTs) - An entity that acquires and holds land and sells any residential buildings that are on the land. Title to the land is held in perpetuity by the CLT and exclusive possessory use of the land is conveyed to the individual homeowners by means of a long term, 99-year ground lease that is assignable to the heirs of the leaseholder and renewable at the end of the 99-year term.

Density - Refers to the number of housing units or square feet of commercial space per unit of land.

Density Bonus - The allocation of development rights that allow a parcel to accommodate additional square footage, or additional residential over the otherwise maximum allowable residential density under the applicable zoning ordinance. Density bonuses can be used as an incentive to a developer who includes affordable units within an otherwise market-priced housing development.

Dwelling Unit - A single unit providing complete independent living facilities for one (1) or more persons, including permanent provisions for living, sleeping, eating, cooking and sanitation, limited to only one (1) kitchen.

Form Based Code A form-based code is a land development regulation that fosters predictable built results and a high-quality public realm by using physical form (rather than separation of uses) as the organizing principle for the code. A form-based code is a regulation, not a mere guideline, adopted into city, town, or county law. A form-based code offers a powerful alternative to conventional zoning regulation.

Exclusionary Zoning - Development regulations that result in the exclusion of low- and moderate-income families from a community.

Extremely Low-Income - Household income at or below 30% Area Median Income.

Fair Housing - Federal law that makes discrimination based on race, color, national origin, religion, sex, family status, or disability illegal when trying to rent or buy a home.

Fair Market Value - The hypothetical price that a willing buyer and seller will agree upon when they are acting freely and with complete knowledge of the situation. Also, fair market value can be what the house is appraised for.

Fair Market Rent (FMR) - HUD's estimate of the actual market rent for a modest apartment in the conventional market.

Gross Monthly Income (GMI) - Household incomes as calculated before taxes or deduction are subtracted.

Growth Center - A growth center is an area designated by a jurisdiction, county, or state for compact, higher density development, which can absorb future growth.

Housing Unit - The place of permanent or customary abode of a person or family. A housing unit has, at least, cooking facilities, bathroom, and sleep quarters.

HUD - U.S. Department of Housing and Urban Development; a cabinet agency of the federal government established for the purposes of providing affordable housing and overseeing housing, economic and community development.

Impact Fee - A fee that is levied on the developer of a project by a city or other public agency as compensation for otherwise-unmitigated impacts the project will produce. Also known sometimes as development fee.

Income-Eligible - Individuals or households with incomes levels that qualify for affordable housing.

Infill Development - Development of vacant land within areas that are already largely developed.

Infrastructure - Facilities and services needed to sustain residential, commercial, industrial, institutional, and other activities.

Land Lease (Ground Lease) - A lease in which the land is rented to the homeowner.

Lease - A contract between landlords and tenants for a possession of space for a specified amount or rent for a specified period of time.

Lien - A legal claim against a property that must be paid off when the property is sold.

Low Income (official HUD definition) - A household whose income does not exceed 80 percent of the median income for the area, as determined by HUD, with adjustments for smaller or larger families.

Median Income - The point at which half the households in an area make less, and half make more.

Mixed-Income - A type of development that includes families with various income levels. Mixed-income developments combine low, moderate and upper income residents in order to decrease economic and social isolation.

Moderate Income (official HUD definition) - A households whose incomes are between 81 percent and 95 percent of the median income for the area, as determined by HUD, with adjustments for smaller or larger families.

Mortgage - A lien on the property that secures the Promise to repay a loan.

NIMBY-ism - Not In My Back Yard. Residents who do not want affordable housing in their community.

Permitting Process - The process of obtaining government approval to build or renovate in compliance with applicable zoning and building codes.

Planned Unit Development (PUD) - A form of development usually characterized by a unified site design for a number of housing units, clustering buildings and providing common open space; density increase; and a mix of building types and land uses. It permits the planning of a project and the calculation of densities over the entire development, rather than on an individual, lot-by lot basis.

Setback - The minimum distance which a wall face or window is required to be from a property boundary or another window to a habitable room.

Shared Parking - Use of the same parking spaces by adjacent uses that have staggered peak periods of demands, thereby reducing the amount of land consumed by parking.

Single-Family Housing - A type of residential structure designed to include one dwelling. Adjacent units may share walls and other structural components but generally have separate access to the outside and do not share plumbing and heating equipment.

Special Needs Housing - Housing developed for and occupied by people with a variety of disabilities who are at risk of homelessness but may not have been literally or chronically homeless.

Subsidize - To assist by payment of a sum of money or by the granting of terms or favors that reduce the need for monetary expenditures. Housing subsidies may take the forms of: mortgage interest deductions or tax credits from federal and/or state income taxes; sale or lease at less than market value of land to be used for the construction of housing; payments to supplement a minimum affordable rent.

Sweat Equity - Value added to a property due to improvements as a result of work performed personally by the owner.

Townhouse - A one-family dwelling in a row of such units in which each unit has its own front and rear access to the outside, no unit is located over another unit, and each unit is separated from any other unit by one or more common and fire-resistant walls.

Transit-Oriented Development - A pedestrian-friendly development focuses around a major transit access point. Elements usually include compact, mixed-use development and facilities and design to enhance the environment for pedestrians.

Vacant - Lands or building that are not actively used for any purpose.

Very Low Income (official HUD definition) - Households whose incomes do not exceed 50 percent of the median area income for the area, as determined by HUD, with adjustments for smaller and larger families.