The Collaborative International Dictionary of English v.0.48:

Chancre \Chan"cre\, n. [F. chancere. See Cancer.] (Med.)
   A venereal sore or ulcer; specifically, the initial lesion of
   true syphilis, whether forming a distinct ulcer or not; --
   called also hard chancre, indurated chancre, and
   Hunterian chancre.
   [1913 Webster]

   Soft chancre. A chancroid. See Chancroid.
      [1913 Webster]

WordNet (r) 3.0 (2006):

chancre
    n 1: a small hard painless nodule at the site of entry of a
         pathogen (as syphilis)