; (15) the term grandchild means the son or daughter of an employee’s son or daughter; (16) the term grandparent means a parent of a parent of an employee; (17) the terms nephew and niece , used with respect to an employee, mean a son or daughter of the employee's sibling; (18) the term parent-in-law means a parent of the spouse or domestic partner of an employee; (19) the term sibling means any person who is a son or daughter of an employee’s parent (other than the employee); (20) the terms son-in-law and daughter-in-law , used with respect to an employee, mean any person who is a spouse or domestic partner of a son or daughter, as the case may be, of the employee; (21) the term State has the same meaning given the term in section 3 of the Fair Labor Standards Act of 1938 ( 29 U.S.C. 203 ); and (22) the terms uncle and aunt , used with respect to an employee, mean the son or daughter, as the case may be, of the employee's grandparent (other than the employee's parent). . (2) Inclusion of adult children and children of a domestic partner Section 6381(6) of such title is amended— (A) by inserting a child of an individual’s domestic partner, after a legal ward,