“Secular knowledge can be useful to understand Torah”
My favorite example:
The Latin word “familia” appeared in a gemara we were learning. I immediately raised my hand to ask the maggid shiur why Chazal used “familia” and not “mishpacha”. Before he could respond a frum high school Latin teacher who was also in the shiur explained that in classical Latin, “familia” has a broader context than do the cognate words today, that it included not just relatives but slaves and servants. Chazal were deliberately using a broader term in order to be specific. Without that understanding from a secular source you would not understand exactly what Chazal meant.