JOSSELIN, a town of the arrondissement of Ploermel, in the department of Finistere, in France. It stands on the river Oust, contains 2692 inhabitants, and has some manufactures of coarse woollen cloths. It is visited in summer on account of celebrated mineral springs. Near to it is a curious cavern called the Pertuis des Fées, or Fairy's Cave, with an arch twenty-five feet in height.