|This article is about an older version of DF.|
Unconscious is the state wherein a dwarf is unable to move or do anything of their own accord. It's noted under the basic wounds screen (iew creature -> ounds).
Dwarves can become unconscious for a variety of reasons. The most common, of course, is that they're sleeping. In combat an injured creature can fall unconscious as well. the most common reason is due to extreme pain from injuries. the amount of pain required to knock out a creature is based on its toughness attribute. Syndromes can also cause periodic unconsciousness as one of their symptoms. Unconscious is different from Rest: dwarves that are unconscious will not heal from their injuries. Very often attacks that hit bones will cause unconsciousness if they chip a bone or worse, due to the high amount of pain bone fractures cause compared to other tissue.
Anything that falls unconscious can be caught in a trap, including creatures normally immune to them. This includes Dwarves, who might decide to take their last nap ever on a tile with 10 Giant Axe Blades.