The term 'street material' can be summarized by the crossword solution of TAR, which is an abbreviation for asphalt TAR. Asphalt TAR is a type of material used in road construction and maintenance. It is a combination of asphalt and TAR that is heated and mixed together to form a sticky, black substance that is then spread over roads and other surfaces. Asphalt TAR is durable and waterproof, making it an ideal material for street surfaces.