In street speak, to represent means to make a symbol or sign identifying a gang affiliation. This man was a Latin King and he is showing their sign. Such signs were used in Chicago’s Uptown during the mid-1970s to show pride in one’s gang, to tell friend from foe, and to salute or greet someone. Sometimes, during this era, people would also refer to such gestures as “signifying.” A quick check of the urban dictionary shows that that meaning seems to have disappeared today. This shot was taken just north of the corner of Winthrop and Ainslie in 1976.