This is the 980th most frequent Russian word.
юных
"Юных" means "young" (genitive or accusative plural, or genitive singular feminine form).
"Юных" is used here as an adjective describing the readers, indicating their youthful or young age.
Эти книги предназначены для юных читателей.
These books are intended for young readers.
"Юных" acts as a descriptive adjective concerning the age of the students, implying they are in the early stages of learning or of a young age.
Учитель заботился о своей группе юных учеников.
The teacher took care of their group of young students.
"Юные" functions as an adjective describing talents, conveying that these are young or early-stage talents.