The Collaborative International Dictionary of English v.0.48:

fibula \fib"u*la\ (f[i^]b"[-u]*l[.a]), n.; pl. fibul[ae]. [L.,
   clasp, buckle.]
   1. A brooch, clasp, or buckle.
      [1913 Webster]

            Mere fibul[ae], without a robe to clasp.
                                                  --Wordsworth.
      [1913 Webster]

   2. (Anat.) The outer and usually the smaller of the two bones
      of the leg, or hind limb, below the knee.
      [1913 Webster]

   3. (Surg.) A needle for sewing up wounds.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fibula
    n 1: the outer and thinner of the two bones of the human leg
         between the knee and ankle [syn: fibula, calf bone]