Transparent overlay is a term used to describe a thin sheet of plastic, usually ACETATE, that is placed over an image or document to protect it. ACETATE is a seven-letter word commonly used to refer to this type of material. It is often used in the printing industry to provide a layer of protection for documents and images. It is also used in the medical field to protect X-rays and other sensitive documents. Transparent overlay is also used in the arts and crafts industry to create stencils and other decorative items.