A sleep that induces visual and audio hallucinations, mostly closed eye, absolutely similar to dreaming, but if something makes you scared, you jump, and shake out of the sleep.
he jumped out of his semi-sleep
by imalinuxfreak November 12, 2007
The area between being awake and asleep. Consisting of eyes closed, body semi to fully relaxed, and still hearing things going on around you. This sleep normally happens at school or some other dull location/event. Semi-sleep is not long, typically lasting no more than 30 minutes.
by Stauder March 28, 2009