Homelessness is the condition of people without a regular dwelling. People who are homeless are most often unable to acquire and maintain regular, safe, secure, and adequate housing, or lack "fixed, regular, and adequate night-time residence." The legal definition of "homeless" varies from country to country, or among different entities or institutions in the same country or region. The term homeless may also include people whose primary night-time residence is in a homeless shelter, a warming center, a domestic violence shelter, a vehicle (including recreational vehicles and campers), cardboard boxes, a tent, tarpaulins, or other ad hoc housing situations. American Government homeless enumeration studies also include persons who sleep in a public or private place not designed for use as a regular sleeping accommodation for human beings. There are a number of organizations who provide provisions for the homeless.