What is the difference between Drywall and Sheetrock®?
Drywall is a generic term that refers to all brands and types of gypsum wallboard panels. Sheetrock® on the other hand is a registered trademark and the brand name of drywall produced by the USG® corporation.
Other companies that make drywall such as the Saint Gobain company which makes CertainTeed brand drywall panels, National Gypsum which makes Gold Bond® brand drywall panels, Continental which makes Bison Board™ brand drywall panels, and others.
Often, the term Sheetrock is mistakenly used to refer to brands of drywall other than those made by USG. No doubt the ubiquitous use of the term Sheetrock is due in part to the fact that drywall under the brand name Sheetrock® was first invented by the USG Corporation in the early 1900s.