The plumbing industry was somewhat surprised when the U.S. Department of Energy (DOE) finalized the definition of showerhead, body spray and safety shower showerhead into federal law. The final rule is available at: https://bit.ly/3qXl1wi.
The definition of showerhead reads, “Showerhead means any showerhead (including a handheld showerhead) other than a safety showerhead. DOE interprets the term “showerhead” to mean an accessory to a supply fitting for spraying water onto a bather, typically from an overhead position.”