For the purposes of this subchapter, the term:
(1) “Child” means a person under the age of 16 years of age.
(2) “District” means the District of Columbia.
(3) “Lawful custodian” means a person who is authorized to have custody by an order of the Superior Court of the District of Columbia or a court of competent jurisdiction of any state, or a person designated by the lawful custodian temporarily to care for the child.
(4) “Relative” means a parent, other ancestor, brother, sister, uncle, or aunt, or one who has been lawful custodian at some prior time.