The Collaborative International Dictionary of English v.0.48:

fibroid \fi"broid\ (f[imac]"broid), a. [L. fibra a fiber +
   -oid.] (Med.)
   Resembling or forming fibrous tissue; made up of fibers; as,
   fibroid tumors. -- n. A fibroid tumor; a fibroma.
   [1913 Webster]

   Fibroid degeneration, a form of degeneration in which
      organs or tissues are converted into fibroid tissue.

   Fibroid phthists, a form of pulmonary consumption
      associated with the formation of fibrous tissue in the
      lungs, and the gradual atrophy of the lungs, from the
      pressure due to the contraction of this tissue.
      [1913 Webster]

WordNet (r) 3.0 (2006):

fibroid
    n 1: benign tumor containing fibrous tissue (especially in the
         uterus) [syn: fibroid tumor, fibroid]