Apprendre le vocabulaire des fruits d’automne

What does “prune” mean in French?

Une prune is a plum, fresh off the tree. The wrinkled dried thing English calls a prune is un pruneau in French — a different word for a different state of the same fruit. So une tarte aux prunes is a plum tart, and asking for des prunes at a market in September gets you fruit, not something from the health-food aisle. The two words are related, which is exactly what makes the swap so easy in both directions.

The fruit also carries a whole idiom: pour des prunes means “for nothing, in vain” — j’ai fait tout ça pour des prunes, “I did all that for nothing.” It goes back to a medieval use of prune for something of no value at all.