«ثُمَّ الْمَشْهُورُ يُطْلَقُ عَلَى مَا حُرِّرَ هُنَا، وَعَلَى مَا اشْتَهَرَ عَلَى الْأَلْسِنَةِ»
The word mashhur is used both for the technical category defined here and for sayings that have become widely repeated.
The first is a technical classification by transmission routes. The second means popular on people’s tongues. A statement may be familiar among preachers, the general public, students, or writers even if the surviving chains do not match that degree of popularity.
Therefore, when someone calls a hadith “famous,” the first question is whether they mean technical mashhur or merely a well-known expression. These two claims require different kinds of evidence.