The Collaborative International Dictionary of English v.0.48:

Shingles \Shin"gles\, n. [OF. cengle a girth, F. sangle, fr. L.
   cingulum a girdle, fr. cingere to gird. Cf. Cincture,
   Cingle, Surcingle.] (Med.)
   A kind of herpes (Herpes zoster) which spreads half way
   around the body like a girdle, and is usually attended with
   violent neuralgic pain.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Herpes zoster \Her"pes zos`ter\, n. (Med.)
   same as shingles; -- a form of herpes caused by the
   varicella-zoster virus.
   [PJC]

WordNet (r) 3.0 (2006):

herpes zoster
    n 1: eruptions along a nerve path often accompanied by severe
         neuralgia [syn: herpes zoster, zoster, shingles]
    2: a herpes virus that causes shingles [syn: herpes zoster,
       herpes zoster virus]