Rubber

1. A yellowish, amorphous, elastic material obtained from the milky sap or latex of various tropical plants, especially the rubber tree, and vulcanized, pigmented, finished, and modified into products such as electric insulation, elastic bands and belts, tires, and containers. Auto tires used to be made of rubber.
2. Any of numerous synthetic elastic materials of varying chemical composition with properties similar to those of natural rubber. My rubber tires and now actually synthetic rubber.
3. A low overshoe made of rubber. We wore rubbers over our shoes on rainy days.