ما وجدت له أفراد كثيرة إما متناهية كالكواكب السيارة
A universal may have many actual instances, yet finitely many, such as planets.
The classical text refers to seven wandering planets according to its historical astronomy. The point is only to illustrate a finite count, not to establish modern astronomical classifications or totals.
In this case many instances belong to a bounded collection. Their being finitely numerous does not prevent “planet” from functioning as a universal concept.