A retirement community, or active ault community, is a very broad, generic term that covers many varieties of housing for retirees and seniors - especially designed or geared for people who no longer work, or restricted to those over a certain age. It differs from a retirement home which is a single building or small complex where no "common areas" for socializing exist. Many retirement communities are planned for that purpose, and have special facilities catering to the needs and wants of retirees, including extensive amenities like clubhouses, swimming pools, arts and crafts, boating, trails, golf courses, and on-site medical facilities. Others have some type of age restrictions but have few if any amenities (these generally don't fit into the "active adult" category). Still others are "Naturally Occurring Retirement Communities" (NORC), which become retirement oriented due to market forces rather than design. Another term may be used for a predominantly senior citizen community, in which residence is unrestricted by age and job affiliation.