The garment in query is a knitted sweater, usually buttoned or zippered, usually that includes the colours and/or symbols related to a particular Greek-letter fraternity. For instance, members of a traditionally Black Greek letter fraternity may put on this sweater to show their affiliation.
Such attire offers a visual illustration of fraternal membership and satisfaction. It fosters a way of unity amongst members and may function a way of figuring out people belonging to the group, each on and off campus. Traditionally, these clothes have been important in demonstrating solidarity and selling the values of the fraternity.
