You are correct, "seclusion" means to be shut away in solitude. As for the sentence, I would need to see more of the text or a brief summary of the topic to better clarify. If I were to guess, some societies place or used to place adolescent girls in seclusion because they wanted to keep them pure until they were given away for marriage. Again, though, the sentence is too isolated and I would need more to better understand the context. I hope this helped!

Greetings, Seclusion is the act of secluding, i.e. shutting out or keeping apart from society, or the state of being secluded, or a place that facilitates it (a secluded place). A person, a couple, or a larger group may go to a secluded place for privacy, or because the place is quiet. Seclusion of a single person is also called solitude. I hope it helps! Regards, Deepika Mantra