brooch: [13] English acquired brooch from Old French broche, a source it returned to a century later to borrow broach. The French word meant ‘long needle’, and at first a brooch was simply a decorative pin whose main function was to fasten a garment. Over the centuries the decorative role has replaced the practical one. => broach
brooch (n.)
early 13c., from Old French broche "long needle" (see broach (n.)). Specialized meaning led 14c. to distinct spelling.