The term 'street border' can be summarized by the crossword solution 'CURB, ' which is a four-letter word. A CURB is a raised edge along the side of a street, sidewalk, or other paved area that serves as a barrier between the street and the adjacent land. Curbs are typically made of concrete, asphalt, or stone and are designed to prevent vehicles from driving onto sidewalks or lawns. They also provide a visual cue to drivers that they are approaching a street corner.