Definition of Immediate relative:
Close family relation such as a parent or sibling. When the term is used in immigration law, it refers to the spouse of a United States citizen, any minor children under the age of 21, and parents of those 21 and older. Permanent residence can be applied for with the initiation by the spouse with US citizenship immediately and are not subjected to specific number limitations on applications for residency as with distant relatives.
Meaning of Immediate relative & Immediate relative Definition