Emily Dickinson Lexicon

PAN'IC, n.¹ [Sp. and It. panico; Fr. panique; Gr. πανικος; W. pannu; to cause to sink, to depress or hollow, to cause a panic. The primary sense is intransitive, to shrink, or transitive, to cause to shrink; hence the fabled Pan, the frightful deity of the woods or shepherds.]

A sudden fright; particularly, a sudden fright without real cause, or terror inspired by a trifling cause or misapprehension of danger; as, the troops were seized with a panic; they fled in a panic.