The garment in query is a knitted sweater, sometimes buttoned or zippered, usually that includes the colours and/or symbols related to a selected Greek-letter fraternity. For example, members of a traditionally Black Greek letter fraternity would possibly put on this sweater to show their affiliation.
Such attire gives a visual illustration of fraternal membership and pleasure. It fosters a way of unity amongst members and might 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.