There is not a single definition of homelessness; although most Federal homelessness programs define a homeless individual as someone who lacks a fixed, regular, and adequate nighttime residence and/or ay person who has a nighttime residence that is (a) supervised publicly or privately in a shelter designed to provide temporary living accommodations, or (b) an institution which provides a temporary residence for a person intending to be institutionalized, or (c) a public or private place not designed specifically for, or that would be ordinarily used as a regular sleeping accommodation for human beings.
A person who is experiencing homelessness has no determined, fixed place to live and quite often dwells in public spaces, shelters, or drop-in centers, or may be doubling-up at the homes of others in a temporary or often makeshift way.
A chronically homeless person is one who is an unaccompanied homeless individual with a disabling condition who has either been homeless for a year or more or has had at least four episodes of homelessness in the past three years.
Unaccompanied individuals who are homeless are those who are not with children or a partner. Disabling conditions include mental disorders, substance abuse disorders or medical conditions often plague the homeless, but this is not always the case and there are many individual reasons for ones homeless condition in our world today.