Trouble starts in muddy water. Latin turba meant 'turmoil' or 'a disorderly crowd,' and turbidus described water that had been stirred up until the sediment clouded it — what we still call turbid. Vulgar Latin formed *turbulare, a verb for the act of muddying or disturbing, and Old French transformed it into trubler. Middle English borrowed both verb and noun in the 13th century, and the concrete image of churned-up water quickly became a metaphor for any kind of disturbance or difficulty. The Latin root turba generated an unusually large family of English words. Turbulent preserves the idea of violent stirring. Disturb adds the prefix dis- (apart) to suggest scattering order. Perturb intensifies the disturbance. And turbine, coined in the 1820s, names a machine that does what the Latin word describes: it harnesses the spinning, churning energy of water or steam. Where trouble is turmoil that harms, a turbine is turmoil put to work. Both remind us that beneath every English word for chaos, there is often a very old image of someone stirring a pool of still water.