Every stock-market crash, every stampede, every episode of mass hysteria that the modern world calls a 'panic' takes its name from a goat-legged deity of ancient Greece. The god Pan — patron of shepherds, wilderness, and flocks — was believed to cause sudden, groundless terror in those who wandered through his domains: the lonely mountain passes, the deep forests, the empty noonday fields. This unexplained dread was his signature power, and the Greeks named it after him.
The word enters English in the early seventeenth century from French 'panique,' which derives from Greek 'πανικός' (panikos), meaning 'of or relating to Pan.' The full Greek expression was 'πανικὸν δεῖμα' (panikon deima), literally 'Pan-terror' or 'Pan-fear' — a fear sent by the god himself. The key quality of this terror was its irrationality: it struck without visible cause, often in isolated places, and frequently affected entire groups simultaneously. Herds of animals would suddenly stampede; armies
The mythological tradition is specific about Pan's role in warfare. At the Battle of Marathon in 490 BCE, according to Herodotus, Pan appeared to the Athenian runner Pheidippides on the road to Sparta and promised to aid the Athenians against the Persians. The subsequent rout of the Persian army — in which a much larger force broke and ran — was attributed in part to the panic that Pan inspired in their ranks. In gratitude, the Athenians established a cult of Pan on the north slope of the Acropolis,
Pan himself was an unusual deity: part human, part goat, associated with the raw, untamed aspects of nature rather than the civilized world of the polis. His name may derive from a PIE root *peh₂- (to protect, to feed — as a guardian of flocks), though the ancient Greeks often connected it folk-etymologically with 'πᾶν' (pan, 'all'), giving rise to the idea that Pan was a universal deity. This false etymology influenced later coinages like 'pandemic' (all the people), 'panorama' (all-seeing), 'panacea' (all-healing), and 'pantheism' (all-god), though these actually derive from the genuine Greek word 'πᾶν' (all) rather than from the god's name.
The word 'panic' was first used in English primarily as an adjective ('panic fear,' 'panic terror') before being nominalized. The purely nominal use — 'a panic' rather than 'a panic fear' — became standard in the eighteenth century. The financial sense ('a panic on the stock exchange') emerged in the eighteenth century, describing the sudden, contagious, and seemingly irrational behavior of markets — a phenomenon that resembled nothing so much as Pan's ancient gift of groundless mass terror. The first major event to be called a financial 'panic' in English was the South Sea Bubble crisis of 1720.