Definition for Insomnia
From Biology Forums Dictionary
1) Insomnia is trouble falling asleep or staying asleep through the night. Episodes may come and go (episodic), last up to 3 weeks (short-term), or be long-lasting (chronic).
2) Insomnia is a sleep disorder that involves difficulty falling or staying asleep, or falling into a sleep that is light, restless, or of poor quality. It can be transient or chronic, and it affects from 10 to 15 percent of the adult population.