Glassify is a relatively uncommon word that describes the process of turning something into glass or giving it a glass-like appearance. There are a variety of synonyms that can be used in place of glassify, including vitrify, anneal, solidify, harden, crystallize, and fuse. Vitrify is a popular synonym that specifically refers to the process of making something glassy by heating it and then rapidly cooling it down, while anneal is often used to describe the process of heating and cooling glass to make it stronger and less prone to shattering. Solidify, harden, and crystallize are more general synonyms that can describe the process of making any substance more rigid, while fuse is often used to describe the process of melting two or more substances together.