As used in this subchapter, unless the context otherwise requires:
(1) “Adoption assistance state” means the state that is signatory to an adoption assistance agreement in a particular case.
(2) “Department” means the District of Columbia Department of Human Services.
(3) “Residence state” means the state where the child is living.
(4) “State” means a state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, the Virgin Islands, Guam, the Commonwealth of the Northern Mariana Islands, or a Territory or Possession of or administered by the United States.