A heavy sheet is a type of fabric that is thicker and heavier than regular fabric. It is usually made from cotton, wool, or synthetic fibers and is used for a variety of purposes such as upholstery, curtains, and bedding. The term 'heavy sheet' can also refer to a large piece of paper or plastic that is used for covering or wrapping items. In this case, the crossword solution for the term 'heavy sheet' is 'PALL', which is a noun meaning a cloth or piece of material used to cover a coffin or bier.