unaccompanied alien child
(2) the term “unaccompanied alien child” means a child who— (A) has no lawful immigration status in the United States; (B) has not attained 18 years of age; and (C) with respect to whom— (i) there is no parent or legal guardian in the United States; or (ii) no parent or legal guardian in the United States is available to provide care and physical custody.