Emotional and physical distress following a traumatic event.
An earthquake that follows in the same vicinity as another, usually larger, earthquake (the "mainshock").
By extension, any result or consequence following a major event.
Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure.
A very bad or frightening dream.
A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis.
To have a nightmare.