The Collaborative International Dictionary of English v.0.48:

Hieroglyphic \Hi`er*o*glyph"ic\, Hieroglyphical
\Hi`er*o*glyph"ic*al\, a. [L. hieroglyphicus, Gr. ?; "iero`s
   sacred + gly`fein to carve: cf. F. hi['e]roglyphique.]
   [1913 Webster]
   1. Emblematic; expressive of some meaning by characters,
      pictures, or figures; as, hieroglyphic writing; a
      hieroglyphic obelisk.
      [1913 Webster]

            Pages no better than blanks to common minds, to his,
            hieroglyphical of wisest secrets.     --Prof.
                                                  Wilson.
      [1913 Webster]

   2. Resembling hieroglyphics; not decipherable. "An
      hieroglyphical scrawl." --Sir W. Scott.
      [1913 Webster]

   3. of or pertaining to hieroglyphs. [WordNet sense 1]
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

hieroglyphical
    adj 1: resembling hieroglyphic writing [syn: hieroglyphic,
           hieroglyphical]
    2: written in or belonging to a writing system using pictorial
       symbols [syn: hieroglyphic, hieroglyphical]