A fixative is a substance used to hold something in place. It can be applied as a GUM, GLUE, or ADHESIVE. GUM is a three-letter word for a type of fixative that is often made from natural resins and used to hold things together. GLUE is a four-letter word for a type of fixative that is usually made from animal by-products and used to stick things together. ADHESIVE is an eight-letter word for a type of fixative that is often made from synthetic materials and used to bond things together.