A metal hearth support is an important component for maintaining a stable and secure fireplace. However, there are alternative synonyms available that can describe this piece of equipment. One possible substitute could be a firebox support, which refers to the metal structure that holds up the firebox in a fireplace. Another option is a grate support, which refers to the metal bars that support the grate in the bottom of the firebox. Additionally, a hearth frame or a firebox frame can be used to describe the metal structure that surrounds and supports the firebox. Regardless of the term used, a sturdy metal support is essential for ensuring a safe and functional fireplace.