A laptop running DOS (or FreeDOS, DR-DOS, PT-DOS, MS-DOS, ect.) usually an older laptop made before 1998 most likely with a Pentium 1 with MMX and 64MB ram at most or a 486 with 4MB of ram. Most commonly used as a way to reminisce about ones childhood.
The dostop I bought off eBay just arrived, I'm going to play some duke3d, doom, quake, and terminal velocity. This brings back lots of good memories.