A condominium is a single unit of real estate—usually a home or residence—in a multi-unit residential development in which each owner of a unit has both a separate ownership interest (often everything inside the front door)—and a common ownership interest (with other unit owners) in the common areas of the property outside the front door—such as roofs, hallways, driveways, walkways, stairways, stucco, brick, paint, stone, and landscaping.

A condominium development is usually governed by a homeowners’ association (HOA) through its board of directors, elected by the homeowners as provided by the HOA’s declaration and bylaws. Unit owners or homeowners in the association are required to pay monthly HOA dues for the maintenance and repair of the common areas of the property and its insurance.

In New York, condominiums are regulated under the New York Condominium Act (Article 9-B of the New York Real Property Law). Each condominium unit owner has an individual ownership interest in their unit, as well as a shared interest in the common elements of the property, such as lobbies, hallways, and recreational facilities. The governance of a condominium is typically handled by a homeowners' association (HOA), which operates through a board of directors elected by the unit owners. The HOA is established by the condominium's declaration and bylaws, which set forth the rules for management and operation of the condominium. Unit owners are required to pay monthly or annual HOA fees to cover the costs of maintaining, repairing, and insuring the common areas, as well as any other expenses agreed upon by the association. These fees are mandatory and failure to pay them can result in liens against the unit and other legal consequences. The HOA also enforces the condominium's rules and regulations, which can affect everything from unit alterations to pet ownership.