They're essentially the same thing. Drywall boards come in three common sizes: 4x8 feet, 4x10 feet, and 4x12 feet. You'll find that there are more thickness options than size options, especially ...

Half-inch drywall is the standard thickness for most applications. When possible, choose lightweight or “ultralight” drywall. It’s about 25 percent lighter than standard 1/2-in. sheets ...