The crossword solution for the term 'THICKISH PIECE' is SLAB, which is a four-letter word. A SLAB is a flat piece of material that is usually thicker than a sheet and can be made from a variety of materials such as stone, wood, metal, or concrete. Slabs are often used in construction, such as for flooring, countertops, and walls. Slabs can also be used for artistic purposes, such as sculptures or monuments.