WordNet (r) 3.0 (2006):

subtitle
    n 1: translation of foreign dialogue of a movie or TV program;
         usually displayed at the bottom of the screen [syn:
         subtitle, caption]
    2: secondary or explanatory title
    v 1: supply (a movie) with subtitles

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "subtitle":
   acknowledgments, back, back matter, banner, banner head,
   bastard title, bibliography, caption, catch line, catchword,
   colophon, contents, contents page, copyright page, dedication,
   drop head, dropline, endleaf, endpaper, endsheet, epigraph, errata,
   flyleaf, folio, fore edge, foreword, front matter, half-title page,
   hanger, head, head up, heading, headline, imprint, index,
   inscription, introduction, jump head, leaf, legend, makeup, motto,
   overline, page, preface, preliminaries, recto, reverso, rubric,
   running head, running title, scarehead, screamer, signature,
   spread, spreadhead, streamer, subhead, subheading, superscription,
   table of contents, tail, text, title, title page, trim size,
   type page, verso