Affordable housing: Generally, housing for which the occupant(s) pay no more than 30 percent of income for costs, including utilities. Some jurisdictions may use other locally determined criteria.

Affordable housing overlay zone:  A zoning district that applies in addition to existing zoning where a jurisdiction encourages provision of affordable housing units.

Below market rate housing:  Units with restricted rents for households ranging from very low to moderate incomes.

Inclusionary zoning: The use of planning ordinances to require a given share of new construction be affordable.

Rent control:  A government-imposed price ceiling on how much a landlord can charge a tenant aimed at mitigating the impact of an escalating or fluctuating rental market. Also known as rent stabilization. California’s state law, the Costa-Hawkins Rental Housing Act, states that rent control does not affect units built after 1995 and does not apply to single-family residences.

Second units: Also called accessory dwelling units, mother-in-law units or granny units. A self-contained accommodation either free standing or attached to an existing home.

Shared housing:  An arrangement in which two or more unrelated people share a residence.

Tiny houses: The “small house” movement is a popular description for the architectural and social movement advocating living simply in small homes. Square footage varies.

The 21 Elements program: A collaborative project encouraging and assisting with producing high-quality Housing Elements in San Mateo County. More broadly, the program aims to develop housing solutions throughout the County.

Impact fees: A one-time charge imposed on new development to offset public services or infrastructure costs

Zoning: The creation of districts classified by restricted lands uses like manufacturing, commercial or residential.