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)

Moby Thesaurus II by Grady Ward, 1.0:

93 Moby Thesaurus words for "chancre":
   French disease, Spanish pox, VD, abscess, acquired syphilis,
   aposteme, balanitis gangrenosa, bed sore, blain, bleb, blister,
   boil, bubo, bulla, bunion, canker, canker sore, carbuncle,
   cerebral tabes, chancroid, chilblain, clap, claps, climatic bubo,
   cold sore, congenital syphilis, constitutional syphilis, dose,
   dose of clap, eschar, felon, fester, festering, fever blister,
   fifth venereal disease, fistula, furuncle, furunculus, gathering,
   general paresis, gonorrhea, granuloma inguinale,
   granuloma venereum, great pox, gumboil, hard chancre, hemorrhoids,
   kibe, latent syphilis, lesion, locomotor ataxia, morbus Gallicus,
   papula, papule, paralytic dementia, paresis, paronychia, parulis,
   petechia, piles, pimple, pock, polyp, pox, pudendal ulcer, pustule,
   rising, scab, simple chancre, social disease, soft chancre, sore,
   stigma, sty, suppuration, swelling, syph, syphilis,
   syphilitic meningoencephalitis, tabes, tabes dorsales,
   tertiary syphilis, tropical bubo, tubercle, ulcer, ulceration,
   venereal disease, wale, welt, wheal, whelk, whitlow, wound