Complex sentence: It is what Saman and his friends used to call each other in high school, and according to the band, it can mean both "an old and close friend" and "an old-fashioned and fusty person"; it depends on the purpose.
Split into simpler sentences: It is what Saman and his friends used to call each other in their high school times. It can mean both an "old and close friend" and an "old-fashioned and fusty person"; it depends on the purpose.