Quiz: Remember the definition of mal de mer?
late 14c., "great fear," from Old French terreur (14c.), from Latin terrorem (nominative terror) "great fear, dread," from terrere "fill with fear, frighten," from PIE root *tre- "shake" (see terrible). Meaning "quality of causing dread" is attested from 1520s; terror bombing first recorded 1941, with reference to German air attack on Rotterdam. Sense of "a person fancied as a source of terror" (often with deliberate exaggeration, as of a naughty child) is recorded from 1883. The Reign of Terror in French history (March 1793-July 1794) so called in English from 1801. Old English words for "terror" included broga and egesa.