The Collaborative International Dictionary of English v.0.48:

flyleaf \flyleaf\ n.
   A blank leaf in the front of back or a book.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

flyleaf
    n 1: a blank leaf in the front or back of a book

Moby Thesaurus II by Grady Ward, 1.0:

44 Moby Thesaurus words for "flyleaf":
   acknowledgments, back, back matter, bastard title, bibliography,
   catch line, catchword, colophon, contents, contents page,
   copyright page, dedication, endleaf, endpaper, endsheet, errata,
   folio, fore edge, foreword, front matter, half-title page, head,
   imprint, index, inscription, introduction, leaf, makeup, page,
   preface, preliminaries, recto, reverso, running title, signature,
   subtitle, table of contents, tail, text, title, title page,
   trim size, type page, verso