The meaning of “bona fide relationship” was not precisely explained, and the phrase has created much uncertainty for migrants and others seeking to travel to the United States from the six countries — Iran, Libya, Somalia, Sudan, Syria and Yemen — covered by the revised travel ban that President Trump issued in March. (An earlier version of the ban included Iraq.)

The Trump administration has now made the definition explicit.

According to a diplomatic cable obtained by The New York Times, “close family” is “defined as a parent (including parent-in-law), spouse, child, adult son or daughter, son-in-law, daughter-in-law, sibling, whether whole or half. This includes step relationships.”

But it went on to state that “close family” does not include “grandparents, grandchildren, aunts, uncles, nieces, nephews, cousins, brothers-in-laws and sisters-in-law, fiancés and any other ‘extended’ family members.”

It is not clear how the administration arrived at the new definitions.

Under existing law, Americans may petition for immigration visas for “immediate relatives” — defined as the parents, spouses and children (under 21) of United States citizens.