Al-mansūb ilā ghayr abīhi
A person identified through someone other than his actual father.
A standard example is al-Miqdād ibn al-Aswad, whose paternal lineage is al-Miqdād ibn ʿAmr. His connection to al-Aswad became famous through an adoptive affiliation, not because al-Aswad was his biological father.
Treating these two designations as different Companions would distort biography and chain analysis. The cause of an attribution—adoption, care, clientage, or residence—must be established and distinguished from paternal descent.