Define “Homeless”

 The United States Code contains the official federal definition of homeless. In Title 42, Chapter 119, Subchapter I, homeless is defined as:

§11302. General definition of homeless individual

(a) In general

For purposes of this chapter, the term “homeless” or “homeless individual or homeless person” includes—

1. an individual who lacks a fixed, regular, and adequate nighttime residence; and
2. an individual who has a primary nighttime residence that is —
   1. a supervised publicly or privately operated shelter designed to provide temporary living accommodations (including welfare hotels, congregate shelters, and transitional housing for the mentally ill);
   2. an institution that provides a temporary residence for individuals intended to be institutionalized; or
   3. a public or private place not designed for, or ordinarily used as, a regular sleeping accommodation for human beings.

(b) Income eligibility

1. In general

   A homeless individual shall be eligible for assistance under any program provided by this chapter, only if the individual complies with the income eligibility requirements otherwise applicable to such program.

2. Exception

   Notwithstanding paragraph (1), a homeless individual shall be eligible for assistance under title I of the Workforce Investment Act of 1998 [29 U.S.C. 2801 et seq.].

(c) Exclusion

For purposes of this chapter, the term “homeless” or “homeless individual” does not include any individual imprisoned or otherwise detained pursuant to an Act of the Congress or a State law.

from http://www.hud.gov/homeless/definition.cfm