«ظَاهِرُهُ الِاتِّصَالُ»
“Its chain appears continuous.”
“Apparently” is deliberate. An isnād may display no obvious missing link yet later investigation reveal concealment, lack of a proven meeting, or another hidden defect. Apparent form does not settle every question of actual transmission.
Example: Two contemporaries may be joined by “ʿan”; chronological overlap alone does not always prove that the particular narration was heard. A specialist must consider their actual encounter and mode of transmission.
Thus musnad is not a synonym for ṣaḥīḥ. The independent criteria of authenticity still have to be established.