This tag is to be used about the Nintendo DS and Nintendo DS Lite units *only*. If your question is about the DSi and the DS XL, please use the [dsi] tag instead. If it is about any of the 3DS's or the 2DS, use the [3ds] tag.
The Nintendo DS is a handheld unit released in 2004 by Nintendo. It features two screens, with the bottom screen touchscreen-capable. It comes with a stylus, and is capable of playing Game Boy Advance games.
The Nintendo DS Lite is a unit released in 2006 by Nintendo. It works just like the NDS, and is noticeably slimmer.