Pervigilium is a Latin term for a night-long vigil or staying awake all night. There are many words that can be used as synonyms for pervigilium, such as insomnia, sleeplessness, restlessness, vigil, wakefulness, and all-nighter. Insomnia and sleeplessness refer to the inability to sleep, whereas restlessness and wakefulness imply being restless and alert without sleeping. A vigil is a period of wakefulness kept for the sake of the dead or the sick, while an all-nighter refers to staying awake for work or study purposes. These synonyms offer various shades of meaning but all describe the experience of staying awake during the night.