fibula UK /ˈfɪb.jʊl.ə/US /ˈfɪb.jəl.ə/ noun2 •The smaller of the two bones in the lower leg. •An ancient kind of brooch used to hold clothing together, similar in function to the modern safety pin.Most of the fibulae have a triangular molding above the notch, which probably contained wound wire. The crossbar is decorated either with a flat knob or with a Persian merlon. — 1949 formsfibulae · fibulae · fibulas