The garment in question is a knitted sweater, typically buttoned or zippered, often featuring the colors and/or symbols associated with a specific Greek-letter fraternity. As an example, members of a historically Black Greek letter fraternity might wear this sweater to display their affiliation.
Such apparel provides a visible representation of fraternal membership and pride. It fosters a sense of unity among members and can serve as a means of identifying individuals belonging to the organization, both on and off campus. Historically, these garments have been significant in demonstrating solidarity and promoting the values of the fraternity.