Accessory Dwelling Unit (ADU)A secondary and independent housing unit located inside of, or on the same lot as, a singlefamily home. State and local laws may have additional restrictions on size and number of bedrooms. 

Affordable Housing: As defined by US Department of Housing and Urban Development, housing (including utilities) that costs no more than 30% of a household’s income. The term is often further limited in federal or state programs to housing with costs less than 30% of 120% of the area median income. For our purposes, we try to use “homes that are affordable” and “affordable housing” interchangeably in the broader sense of meeting our households needs at a price they can afford. 

Apartment Building: A residential building, typically multi-story, that is larger than a multi-unit dwelling and where units are more commonly rented than owned. 

Area median Income (AMI): The midpoint of a region’s household income distribution – half of families in a region earn more than the median and half earn less than the median. AMI is a common figure used in affordable housing that is calculated annually by county by the US Department of Housing and Urban Development (HUD). 

Boarding House: A structure that provides short or longer-term accommodations, generally consisting of a private bedroom and shared common space. Also known as a rooming house. 

Bungalow Court cluster of several free-standing homes arranged around a central open space, often in an oblong formation arranged perpendicular to the road. Also known as a cottage court. 

CohousingA group of homes linked by physical proximity, common spaces and facilities, and participatory governance structures. 

Community Land Trust: A private, non-profit organization that holds title to a collection of parcels scattered over its service area. This model increases access to homeownership by decoupling land prices and building prices. Community land trusts can be used to increase the supply of affordable housing by leasing the land under a home for a nominal fee, setting affordable unit quotas for developers, and imposing home resale price restrictions. 

CondominiumAn ownership model where several attached housing units, typically multi-story, may be separately owned, but that have a joint agreement, typically covering joint ownership and maintenance of grounds and the building’s exterior.   

Duplex: A residential structure with two housing units. 

Emergency Housing: A short term accommodation for adults, families, and children who are homeless or in crisis.

Employer-Assisted HousingPrograms where employers help employees locate affordable housing, understand the process of homeownership, provide financial assistance in the form of loans, grants, matched savings plans, etc., or even supply homes. 

FormBased Code: A type of provision in zoning that focuses more on the structure’s look and size than on the use inside. See for more information. 

Home: Wherever you live is your home, whether it is a rental apartment, condo, part of a house, or a single detached home you own. The term “housing” or “housing unit” is used for technical purposes; however “homes” means the same with fewer negative connotations. We need all types of homes and none should be stigmatized. 

Homebuyer Assistance: A number of programs, often government funded, that help low- and moderate-income households purchase a home. Examples include: down payment and closing cost assistance, subsidized interest rates, first-time homebuyer counseling and education, etc.  

Home Resale Restrictions: Restrictions enacted by a property owner to ensure long-term affordability of a property such as homebuyer income qualifications, deed restrictions that limit resale price, prohibitions on leasing, limits on permissible renovationsetc. 

Homesharing: An arrangement between 2 or more unrelated people to share common areas of a home, while maintaining private bedrooms. Non-owners pay rent and/or provide help around the home. The term is both informal, as well as a formal program called “HomeShare” that vets and matches possible owners and co-habitants. Visit for more information. 

Housing unit (dwelling): A structure, or part of a structure, that is residential in nature and includes a kitchen, bedroom and bathroom. Also see Home. 

HUD: US Department of Housing and Urban Development. 

Housing with Supportive Services: Housing with supportive services provides safe homes, whether transitional or permanent, in conjunction with needed services. These services can include but are not limited to vocational training, mental health care, addiction services, or life skills services. These homes may exist in a permanent location or be available for any home deemed appropriate. This definition includes but is not limited to the supportive housing model used by many publicly funded programs. Also see Supportive Housing. 

Incentives, Affordable Housing: In zoning or subdivision, these may lessen lot size, coverage, density, or other requirements for developments that include a certain percentage of affordable units. Employers may also offer incentives such as down payment assistance. 

Inclusionary zoning: Local zoning that requires the inclusion of affordable housing units in new development, usually through a mandated percent of the new units or payment to a housing fund 

Infill DevelopmentNew development on vacant lots within built areas or redevelopment in already built areas, for the purpose of maximizing use of available land in core areasensuring the efficiency of public utilities and infrastructure, and maintaining the integrity and vitality of downtowns and village centers. 

Live/Work Unit: A multi-story building, often within a village, that includes one dwelling unit above or behind a fire-separated, non-residential ground floor space.   The nonresidential and residential units typically have separate street entrances.  This is similar to a mixed-use building, except a live/work unit is limited to only two units.   

Low Income Housing Tax Credit (LIHTC) ProgramFederal tax incentive program, administered by state-designated agencies, to promote the development of new affordable rental units. Federal income tax credits have a lifespan of 10 years, and participating properties are committed to meet specific affordability thresholds for 99 years. 

Market-rate: A term used to denote that the housing does not have a subsidy. 

Manufactured Home: A home built in the controlled environment of a manufacturing plant and transported in one or more sections on a permanent chassis. Also see Manufactured Home Park 

Manufactured Home Park: Any property with three or more mobile homes or mobile home lots. See also Manufactured Home. 

Micro-UnitsVery small apartments that are typically open concept and under 400 square feet, sometimes with access to common spaces. 

Missing Middle Housing: A term to describe housing that can be built that is affordable to households (often above federal housing income limits) without subsidies and that arstill lacking. See for more information. 

Modular House: A single-detached home, except that the house was constructed in components in a factory and assembled on-site. See also Single-detached house. 

Multi-family/Multi-unit Housing: A residential structure, or cluster of structures, with three and more housing units. 

Tax Increment Financing (TIF)Within a designated TIF area (“district”) and a set time period, a local government finances infrastructure to enable development projects by issuing a bond backed by the anticipated increase in property tax revenues. 

Tiny Home: A fully-equipped, free-standing home averaging between 100 and 400 square feet. They come in two forms; those on wheels and those on a foundation.   

Townhouse  Small-to medium-sized attached dwellings usually 2-3 stories tall with adjacent units placed side-by-side. 

Triplex: A residential structure with 3 housing units. 

Short-term Rental (STR): A rental housing unit meant for short-term stays such as an AirBnB 

Single-detached house: A structure for habitation by one household that provides complete independent living facilities, including permanent provisions for living, sleeping, eating, cooking and sanitation. Often referred to as a single-family dwelling or simply a house. 

Supportive Housing: A regulatory-based housing model for vulnerable families and individuals that provides tenants with voluntary social services and subsidizes rent to maintain affordability (typically under 30% of household income). Support services can be tied to a structure, such as a group home, or simply provided to a person at their own residence. Also see Homes with Supportive Services. 

Workforce HousingAffordable housing that is in close proximity to employment centers, and is typically associated with members of the community who are gainfully employed. The term is used to cover housing that is affordable, but beyond many state and federal income limits on affordable housing, often for 100-200% of area median income