Insomnia: Lack of sleep
Melatonin: A brain hormone secreted in darkness which induces sleep.
Caffeine: A substance present in coffee and cocoa products, which is a stimulant and hence suppresses sleep
Polysomnogram: An overnight sleep study in which various stages of sleep and the related events are studied.
CPAP: Continuous positive airway pressure, in which a steady stream of air keeps the breathing passage functioning.
Behavioral therapy: A therapy focused on removing the unpleasant phobias related to sleep and to help people adopt good sleep hygiene.