As used in this chapter: I. "State" includes any state, territory or possession of the United States, the District of Columbia and the Commonwealth of Puerto Rico. II. "Obligor" means any person owing a duty of support. III. "Obligee" means any person to whom a duty of support is owed. IV. "Child" means either a natural or adopted child. V. "Father" or "mother" means either a natural or adopted father or mother.