Also known as: ペンタブレット, ペンタブ, 液晶ペンタブレット, 液晶タブレット, 液タブ, 板タブ, 板タブレット
On Danbooru this will typically refer to a flat, rectangular surface used as a tactile interface to a computer-based drawing program. Often this is used in conjunction with a Stylus, to better approximate the handling of a real-life pen, pencil or brush.
For the computers that incorporates a built in touchscreen see the Tablet Pc tag. Not to be confused with a Stone Tablet.