The term 'diamond rubber' refers to a type of rubber that is made up of diamond-shaped particles. It is often used in industrial applications, such as for making plates and slabs. The crossword solutions for the term 'diamond rubber' are SLAB (4 letters) and PLATE (5 letters). SLAB is a flat piece of material, usually rectangular or square in shape, while PLATE is a flat object with a thickness greater than that of a sheet. Both of these materials can be made from diamond rubber, which is known for its strength and durability.