hang by a thread, to

To be in a precarious situation. This expression comes from the story of Damocles, a servile courtier to Dionysius I of Syra- cuse. Tired of hearing Damocles praise him to the skies, Dionysius invited him to a magnificent banquet. Seated there, Damocles looked up and saw a naked sword suspended over his head by a single hair, whereby the king intended to show his servant the insecurity of his position. By the sixteenth century the story had been converted into a proverb, “It hangs by a hair,” listed in Erasmus’s Adagia (1523), and in the course of time hair was changed to thread.