Gharīb nisbī (غریب نسبی) is a Hadith that is not limited to one narrator at the start of its sanad, but has just one narrator in a later generation.
• In the Successors' generation, transmission is not limited to one narrator.
• In a generation after that, one narrator transmits it alone.
It is also called fard nisbī (فرد نسبی). Looking only at a later generation is not enough; the condition at the start also matters.