Definition 1: ADU is an abbreviation for Affordable Dwelling Unit. ADU programs allow covenants to be placed on newly constructed housing to create affordable housing units. Units are sold or rented at below the market value and the rent, value, and resale price of the units are restricted for a certain time period

Definition 2: ADU is an abbreviation for Accessory Dwelling Unit. An ADU is a secondary dwelling unit established in conjunction with and clearly subordinate to a single family detached dwelling unit.